Fix: soften fallback handler warning

[katspaugh]

What it solves

The original custom fallback handler warning was added in #1781.

We got feedback from CowSwap that the current warning is too scary to the users when they enable a custom handler for TWAP orders. So we're changing the icon and message to be less alerting.

Official:

Custom:

Unset:

[github-actions]

Branch preview

✅ Deploy successful!

https://fallback--walletweb.review-wallet-web.5afe.dev

[schmanu]

If the CowSwap TWAP fallback handler is also static we could allowlist it's address instead. If it is a completely unknown fallback handler I would prefer a warning.
What do you think?

[katspaugh]

@schmanu allowlist where?

[github-actions]

ESLint Summary View Full Report

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Type	Occurrences	Fixable
Errors	0	0
Warnings	0	0
Ignored	0	N/A

• Result: ✅ success
• Annotations: 0 total

---

^{Report generated by eslint-plus-action}

[github-actions]

Coverage report

St.❔	Category	Percentage	Covered / Total
🟡	Statements	75.26% (+0.11% 🔼)	9402/12492
🔴	Branches	49.55% (+0.17% 🔼)	1929/3893
🔴	Functions	58.18% (+0.3% 🔼)	1419/2439
🟡	Lines	76.9% (+0.07% 🔼)	8509/11065

Show files with reduced coverage 🔻

St.❔	File	Statements	Branches	Functions	Lines
🔴	... / module.ts	8.99% (-1.24% 🔻)	15.38%	7.41% (-0.28% 🔻)	10.26% (-1.28% 🔻)

Test suite run success

1044 tests passing in 142 suites.

Report generated by 🧪jest coverage report action from 507a1c0

[schmanu]

@schmanu allowlist where?

For now we could have a list in our repo of known fallback handler addresses where we add the CoW Extensible Fallback Handler addresses
But ideally that would live on the config service / gateway.

I'm just thinking in general having an unexpected / inofficial fallbackhandler hints at a potentially risky setup. Or do we know many other dApps / protocols that use custom fallback handlers?

[katspaugh]

If you're implying hardcoding it, I wouldn't do it.

[liliya-soroka]

All custom fallbackhandlers will be green after the fix . I would check with the prod team if it's expected and safe

[katspaugh]

Fixed. ✅

Official:

Custom:

Unset:

[liliya-soroka]

Verified