[Quote V5 Support] Implement TDX Quote V5 Proto to Bytes Conversion

[Sourabh-25]

This change adds the functionality to serialize the TDX Quote Format V5 protobuf messages back into their raw little-endian ABI byte format. This complements the byte-to-proto parsing added in the previous PR.

NOTE: Stacked PR: This builds on top of my previous pending PR . Please ignore the first commits and only review the final commit which implements quoteToAbiBytes.
Key changes:

• Proto to Bytes Serialization:

  • Updated QuoteToAbiBytes to dispatch to quoteToAbiBytesV5 for pb.QuoteV5 types.
  • Implemented quoteToAbiBytesV5: Converts the main pb.QuoteV5 message to bytes.
    • Implemented TdQuoteBodyDescriptorToAbiBytes: Converts the pb.TDQuoteBodyDescriptor message to bytes.
    • Implemented TdQuoteBodyV5ToAbiBytes: Converts the pb.TDQuoteBodyV5 message to bytes, handling differences between TDX 1.0 and 1.5 body types.

• Unit Tests:

  • Added tests in abi_test.go to verify the correctness of the proto-to-bytes conversions.
  • Ensured round-trip conversion integrity: The raw bytes obtained from QuoteToAbiBytes(QuoteToProto(test.RawQuoteV5)) match the original test.RawQuoteV5.
  • Added test cases for nil and invalid inputs for the new TdQuoteBodyDescriptorToAbiBytes and TdQuoteBodyV5ToAbiBytes functions in TestNilToAbiBytesConversions and TestInvalidConversionsToAbiBytes.