chore: PermissionlessGenericHandler: unpack depositor address with custom length

[viatrix]

Description

Currently executionDataDepositor address is decoded in deposit function on origin chain as abi.decode so its length is not used here and the address is read as 32 bytes (20 bytes padded with 0).
This change implements parsing of executionDataDepositor in the same way as executeContractAddress, using its length (20 bytes for EVM).

Related Issue Or Context

We had different encodings of executionDataDepositor and executeContractAddress addresses: one of them was encoded using 32 bytes and another one was encoded using 20 bytes (for EVM chains). This change would make the encoding consistent.

Closes: #

How Has This Been Tested? Testing details.

Unit tests were updated.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation

Checklist:

• I have commented my code, particularly in hard-to-understand areas.
• I have ensured that all acceptance criteria (or expected behavior) from issue are met
• I have updated the documentation locally and in chainbridge-docs.
• I have added tests to cover my changes.
• I have ensured that all the checks are passing and green, I've signed the CLA bot

[lastperson]

Suggested change

	executionDataDepositor: bytes bytes 36 + len(executeFuncSignature) + len(executeContractAddress) - 36 + len(executeFuncSignature) + len(executeContractAddress) + len(executionDataDepositor)
	executionData: bytes bytes 36 + len(executeFuncSignature) + len(executeContractAddress) + len(executionDataDepositor) - END
	executionDataDepositor: bytes bytes 36 + len(executeFuncSignature) + len(executeContractAddress) - 36 + len(executeFuncSignature) + len(executeContractAddress) + len(executionDataDepositor)
	executionData: bytes bytes 36 + len(executeFuncSignature) + len(executeContractAddress) + len(executionDataDepositor) - END