improve builder default envs

[MasterHW]

Fixes: bug "REACT_APP_CHAINS_OVERRIDE=all" is not valid, and commenting out this line will actually have the desired effect. Also, make allo-v2 the default.

Description

Improve default/example env values to more closely reflect "ideal" default values.

Checklist

This PR:

• Does it add new payout or donation token? In this case, have they been added to the indexer to avoid it to crash?
• Includes only changes relevant to the original ticket. Significant refactoring needs to be separated.
• Doesn't disable eslint rules.
• Doesn't work around the type checker (including but not limited to: type casts, non-null assertions, @ts-ignore, unjustified optional values).
• Doesn't contain commented out code.
• If adding/updating a feature, it adds/updates its test script on Notion.

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Name	Status	Preview	Comments	Updated (UTC)
builder	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	May 16, 2024 2:34pm
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manager-staging	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	May 16, 2024 2:34pm