chore: bump GB to enable slashing

[robert-zaremba]

Description

Bumps GB to enable slashing and tests in GB.

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Author Checklist

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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 or client breaking change
• added appropriate labels to the PR
• targeted the correct branch (see PR Targeting)
• provided a link to the relevant issue or specification
• added a changelog entry to CHANGELOG.md
• 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

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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 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
• manually tested (if applicable)

[toteki]

Moved a line on the changelog - everything else utACK