Fix "Learn more" link on Connected Account notification

[ryanml]

Fixes: #16276

Also updates the casing of the "Learn more" text

Manual Testing Steps

1. Unlock MM
2. Connect to Test Dapp
3. Open MM popup
4. Click "Learn more" from the Connected account notification
5. Ensure the user navigates to https://metamask.zendesk.com/hc/en-us/articles/4405506066331-User-guide-Dapps

Pre-Merge Checklist

• PR template is filled out
• IF this PR fixes a bug, a test that would have caught the bug has been added
• PR is linked to the appropriate GitHub issue
• PR has been added to the appropriate release Milestone

+ If there are functional changes:

• Manual testing complete & passed
• "Extension QA Board" label has been applied

[metamaskbot]

Builds ready [f621a10]

• builds: chrome, firefox, opera
• builds (beta): chrome, firefox, opera
• builds (flask): chrome, firefox, opera
• build viz: Build System
• mv3: Background Module Init Stats
• mv3: UI Init Stats
• mv3: Module Load Stats
• mv3: Bundle Size Stats
• mv2: E2e Actions Stats
• code coverage: Report
• storybook: Storybook
• typescript migration: Dashboard
• all artifacts
• bundle viz:

  • background: 0, 1, 2, 3, 4
  • common: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
  • content-script: 0
  • contentscript: contentscript
  • disable-console: disable-console
  • inpage: inpage
  • policy-load: policy-load
  • sentry-install: sentry-install
  • ui: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9

Page Load Metrics (2206 ± 78 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	92	292	116	42	20
		domContentLoaded	1772	2369	2188	150	72
		load	1772	2405	2206	163	78
		domInteractive	1772	2369	2188	150	72

[legobeat]

LGTM. Aside: localisations are inconsistent on casing of learnMore where most languages have it with leading upper-case identical to learnMoreUpperCase (e.g. Spanish, French, German, Danish) and some don't (English, Turkish).