fix: add missing inETH, instETH gauges on Arbitrum

[Xeonus]

Description

Please include a summary of the change and if relevant which issue is fixed. Please also include relevant motivation and context.

Type of change

• [ x] Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Dependency changes
• Code refactor / cleanup
• Documentation or wording changes
• Other

How should this be tested?

Please provide instructions so we can test. Please also list any relevant details for your test configuration.

• Test A
• Test B

Visual context

Please provide any relevant visual context for UI changes or additions. This could be static screenshots or a loom screencast.

Checklist:

• [x ] I have performed a self-review of my own code
• I have requested at least 1 review (If the PR is significant enough, use best judgement here)
• I have commented my code where relevant, particularly in hard-to-understand areas
• If package-lock.json has changes, it was intentional.
• [ x] The base of this PR is master if hotfix, develop if not

[vercel]

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Name	Status	Preview	Comments	Updated (UTC)
beta-app-v2	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Jul 11, 2024 7:10am

1 Skipped Deployment

Name	Status	Preview	Comments	Updated (UTC)
app-v2	⬜️ Ignored (Inspect)			Jul 11, 2024 7:10am

[Xeonus]

Tested staking flow for both pools in preview build.
Gauge proposals:
https://forum.balancer.fi/t/bip-646-enable-gauge-for-insteth-wsteth-arbitrum/5834
https://forum.balancer.fi/t/bip-645-enable-gauge-for-ineth-wsteth-arbitrum/5832