fix!: update gov MaxMetadataLen

[doggystylez]

Description

Closes: #XXXX

in the recent sdk version upgrade, the metadeta length for gov props was set to default 255, which affects the description field for legacy (and new?) proposals. see:

https://www.mintscan.io/cosmos/proposals/893
https://www.mintscan.io/cosmos/proposals/895

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Author Checklist

All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.

I have...

• Included the correct type prefix in the PR title
• Added ! to the type prefix if API, client, or state breaking change (i.e., requires minor or major version bump)
• Targeted the correct branch (see PR Targeting)
• Provided a link to the relevant issue or specification
• Followed the guidelines for building SDK modules
• Included the necessary unit and integration tests
• Added a changelog entry in .changelog (for details, see contributing guidelines)
• Included comments for documenting Go code
• Updated the relevant documentation or specification
• Reviewed "Files changed" and left comments if necessary
• Confirmed all CI checks have passed

Reviewers Checklist

All items are required. Please add a note if the item is not applicable and please add
your handle next to the items reviewed if you only reviewed selected items.

I have...

• confirmed the correct type prefix in the PR title
• confirmed ! in the type prefix if API or client breaking change
• confirmed all author checklist items have been addressed
• reviewed state machine logic
• reviewed API design and naming
• reviewed documentation is accurate
• reviewed tests and test coverage

[MSalopek]

Thank you for your contribution!

Could you link to the code line that defined this value in old gaia versions (or cosmos-sdk versions)?

On v47 it seems that all text fields are subject to the same assertions which may be a bit too strict:

• https://github.com/cosmos/cosmos-sdk/blob/v0.47.11-ics-lsm/x/gov/keeper/proposal.go#L22

Providing more context:

On cosmos-sdk v0.47 you can submit text proposals via gaiad tx gov submit-legacy-proposal (the "old" text proposals) and via gaiad tx gov submit-proposal.

Both ways of submitting proposals are affected.