Move MsgSubmitProposal of group module to non-determinstic gas

[TxCorpi0x]

Description

This pull request updates the deterministic gas configuration for group messages by moving MsgWithdrawProposal from the deterministic to the non-deterministic category. This change ensures more consistent gas estimation logic for proposal-related messages and updates the associated tests to reflect the new categorization.

Changes to gas configuration logic:

• Removed MsgWithdrawProposal from the deterministic gas mapping in DefaultConfig, so it no longer uses a fixed gas value.
• Added MsgWithdrawProposal to the list of non-deterministic messages in DefaultConfig, aligning its treatment with other proposal-related messages.

Test updates:

• Updated TestDeterministicGas_DeterministicMessages to reflect the new counts: increased non-deterministic messages by one and decreased deterministic messages by one.

Reviewers checklist:

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Authors checklist

• Provide a concise and meaningful description
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