fix: prune nested proofs to prevent header size error (#181)

[Harsh10022004]

Description

Fixes #181.

This PR addresses the "maximum agent message header size exceeded" error that occurs during delegation storage (access/delegate). The crash was caused by the system including the full history of nested proofs in the invocation header.

Solution

• Implemented a pruning mechanism to adhere to the requested fix of stripping unnecessary blocks in the Guppy client.
• Added the pruneDelegation helper function which ensures only the single root block of the delegation is included in the message, significantly reducing payload size and preventing the crash.

Verification

Tested by running existing and new regression tests within the package.

Command:

go test -v ./pkg/client -run TestAccessDelegate