chore: remove unused error handling & misc. fixes

[elmutt]

Description

• Dont let trade continue with invalid amount -- fixes bug - trade widget builds tx of $1 without inputting any values #1803
• Check approval before trying to build trade -- fixes error toast with contract approval #1816 & white screen when approving a contract on windows  #1813
• Build trade after approval completes
• Remove unused error handling code
• Get minimum from already existing quote instead of making more swapper api calls to get minMax (performance)
• Get estimated fee for sendMax from existing quote instead of getting a new quote (performance)

Notice

• Have you followed the guidelines in our Contributing guide?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Pull Request Type

• 🐛 Bug fix (Non-breaking Change: Fixes an issue)
• 🛠️ Chore (Non-breaking Change: Doc updates, pkg upgrades, typos, etc..)
• 💅 New Feature (Breaking/Non-breaking Change)

Issue (if applicable)

Risk

Low risk. fixes a couple swapper regressions and general cleanup

Testing

See that you cant click through a trade with 0 amount entered.
See that swapping is not borked in general

Screenshots (if applicable)

[cloudflare-pages]

Deploying with    Cloudflare Pages

Latest commit:	46cdf70
Status:	✅  Deploy successful!
Preview URL:	https://4cb51fa2.web-29e.pages.dev

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[theoboldfrazier]

Looks good.

[0xdef1cafe]

approved with comments - please click accept on suggestions and i'll restamp

[elmutt]

approved with comments - please click accept on suggestions and i'll restamp

done. If only this cypress test would pass

[elmutt]

approved with comments - please click accept on suggestions and i'll restamp

I had to undo those changes. it doesnt quite fit

[0xApotheosis]

🍭