Remove unused FF_HOOK_EVENTS (#1026)

- Removes `FF_HOOK_EVENTS` from the service configuration.
- Changes `signals.py` classes for both Chains and Safe Apps, so these classes don't use the `/v2/flush/` endpoint anymore. (And modifies their test counterparts accordingly)
- Removes the `flush` function from the Safe Client Gateway client implementation.

src/chains/signals.py

@@ -1,11 +1,10 @@
 import logging
 from typing import Any
 
-from django.conf import settings
 from django.db.models.signals import m2m_changed, post_delete, post_save, pre_delete
 from django.dispatch import receiver
 
-from clients.safe_client_gateway import HookEvent, flush, hook_event
+from clients.safe_client_gateway import HookEvent, hook_event
 
 from .models import Chain, Feature, GasPrice, Wallet
 
@@ -16,22 +15,14 @@
 @receiver(post_delete, sender=Chain)
 def on_chain_update(sender: Chain, instance: Chain, **kwargs: Any) -> None:
     logger.info("Chain update. Triggering CGW webhook")
-    if settings.FF_HOOK_EVENTS:
-        hook_event(HookEvent(type=HookEvent.Type.CHAIN_UPDATE, chain_id=instance.id))
-    else:
-        flush()
+    hook_event(HookEvent(type=HookEvent.Type.CHAIN_UPDATE, chain_id=instance.id))
 
 
 @receiver(post_save, sender=GasPrice)
 @receiver(post_delete, sender=GasPrice)
 def on_gas_price_update(sender: GasPrice, instance: GasPrice, **kwargs: Any) -> None:
     logger.info("GasPrice update. Triggering CGW webhook")
-    if settings.FF_HOOK_EVENTS:
-        hook_event(
-            HookEvent(type=HookEvent.Type.CHAIN_UPDATE, chain_id=instance.chain.id)
-        )
-    else:
-        flush()
+    hook_event(HookEvent(type=HookEvent.Type.CHAIN_UPDATE, chain_id=instance.chain.id))
 
 
 # pre_delete is used because on pre_delete the model still has chains
@@ -40,12 +31,9 @@ def on_gas_price_update(sender: GasPrice, instance: GasPrice, **kwargs: Any) ->
 @receiver(pre_delete, sender=Feature)
 def on_feature_changed(sender: Feature, instance: Feature, **kwargs: Any) -> None:
     logger.info("Feature update. Triggering CGW webhook")
-    if settings.FF_HOOK_EVENTS:
-        # A Feature change affects all the chains that have this feature
-        for chain in instance.chains.all():
-            hook_event(HookEvent(type=HookEvent.Type.CHAIN_UPDATE, chain_id=chain.id))
-    else:
-        flush()
+    # A Feature change affects all the chains that have this feature
+    for chain in instance.chains.all():
+        hook_event(HookEvent(type=HookEvent.Type.CHAIN_UPDATE, chain_id=chain.id))
 
 
 @receiver(m2m_changed, sender=Feature.chains.through)
@@ -54,13 +42,8 @@ def on_feature_chains_changed(
 ) -> None:
     logger.info("FeatureChains update. Triggering CGW webhook")
     if action == "post_add" or action == "post_remove":
-        if settings.FF_HOOK_EVENTS:
-            for chain_id in pk_set:
-                hook_event(
-                    HookEvent(type=HookEvent.Type.CHAIN_UPDATE, chain_id=chain_id)
-                )
-        else:
-            flush()
+        for chain_id in pk_set:
+            hook_event(HookEvent(type=HookEvent.Type.CHAIN_UPDATE, chain_id=chain_id))
 
 
 # pre_delete is used because on pre_delete the model still has chains
@@ -69,12 +52,9 @@ def on_feature_chains_changed(
 @receiver(pre_delete, sender=Wallet)
 def on_wallet_changed(sender: Wallet, instance: Wallet, **kwargs: Any) -> None:
     logger.info("Wallet update. Triggering CGW webhook")
-    if settings.FF_HOOK_EVENTS:
-        # A Wallet change affects all the chains that have this wallet
-        for chain in instance.chains.all():
-            hook_event(HookEvent(type=HookEvent.Type.CHAIN_UPDATE, chain_id=chain.id))
-    else:
-        flush()
+    # A Wallet change affects all the chains that have this wallet
+    for chain in instance.chains.all():
+        hook_event(HookEvent(type=HookEvent.Type.CHAIN_UPDATE, chain_id=chain.id))
 
 
 @receiver(m2m_changed, sender=Wallet.chains.through)
@@ -83,10 +63,5 @@ def on_wallet_chains_changed(
 ) -> None:
     logger.info("WalletChains update. Triggering CGW webhook")
     if action == "post_add" or action == "post_remove":
-        if settings.FF_HOOK_EVENTS:
-            for chain_id in pk_set:
-                hook_event(
-                    HookEvent(type=HookEvent.Type.CHAIN_UPDATE, chain_id=chain_id)
-                )
-        else:
-            flush()
+        for chain_id in pk_set:
+            hook_event(HookEvent(type=HookEvent.Type.CHAIN_UPDATE, chain_id=chain_id))