Review using of CallOptions in MsgVoteInbound

[lumtis]

Describe the Issue In MsgVoteInbound for a deposit and call on ZetaChain a CallOptions containing a gas limit of 1.5M is added by the observer.

This value is unused since the gas limit is defined by the gateway gas limit value defined in https://github.com/zeta-chain/node/issues/4152

We should check:

• This value be made deprecated
• Added more notes that it is currently unused because it is confusing for the codebase currently. Eventually in the future this value could be used: example: the developers pay an additional fee on the source chain to allow setting a higher gas limit than default in the depositAndCall