refactor: convert WebLnProvider into hook

[ekzyis]

Description

Instead of using a component that only uses useEffect to hook into WebLN events from the browser extension, we can just call useEffect in a custom hook like we already do for other hooks.

Additional context

This is targeting the wallets branch instead of master, because the changes here depend on the changes in wallets that have not been merged yet into master (#2572).

I did not want to port the code back to master since it's not that important so I'd rather just not have to resolve a conflict later.

Checklist

Are your changes backward compatible? Please answer below:

yes

On a scale of 1-10 how well and how have you QA'd this change and any features it might affect? Please answer below:

8. WebLN wallet still disabled when lightning browser extension is disabled

For frontend changes: Tested on mobile, light and dark mode? Please answer below:

n/a

Did you introduce any new environment variables? If so, call them out explicitly here:

no

Did you use AI for this? If so, how much did it assist you?

no

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Note

Convert the WebLnProvider component into a useWeblnEvents hook and wire it into global wallet hooks, removing the provider wrapper.

• Wallets (client):
  • Replace WebLnProvider usage in wallets/client/hooks/global.js with useWeblnEvents() inside WalletHooks, removing the provider wrapper around children.
• WebLN protocol:
  • Convert component WebLnProvider to hook useWeblnEvents in wallets/lib/protocols/webln.js to manage webln:enabled/disabled events and set window.weblnEnabled for isAvailable.

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[ekzyis]

Base automatically changed from wallets to master last week

wow, this is cool, GitHub realized I wanted to merge this into #2572, but #2572 was merged into master (and the wallets branch deleted), and thus this PR now also points to master as it should