Fix Inefficient Cloning in From<BigDecimal> for MmNumber

[laruh]

The current implementation of From for MmNumber unnecessarily takes ownership of BigDecimal, but then immediately borrows it with from_dec_to_ratio(&n), making the move redundant. Since the function only needs a reference, we should implement From<&BigDecimal> to allow efficient conversion without cloning.
see #2112 (comment) - we clone BigDecimal amount in so many places.

komodo-defi-framework/mm2src/mm2_number/src/mm_number.rs

Lines 102 to 104 in ff0eefc

	impl From<BigDecimal> for MmNumber {
	fn from(n: BigDecimal) -> MmNumber { from_dec_to_ratio(&n).into() }
	}

Rust allows implementing both From<BigDecimal> and From<&BigDecimal>, we can support both ownership-based and reference-based conversions.