chore: Remove broken coverage report link (#29410)

## **Description**

The unit test coverage report was previously available in the
`metamaskbot` comment, but this link has been broken since we migrated
unit tests from CircleCI to GitHub Actions in #25570

The broken link has been removed for now. It can be restored in the
future, after migrating the `metamaskbot` comment to GitHub actions as
well.

[![Open in GitHub
Codespaces](https://github.com/codespaces/badge.svg)](https://codespaces.new/MetaMask/metamask-extension/pull/29410?quickstart=1)

## **Related issues**

N/A

## **Manual testing steps**

Check that the broken link is no longer shown in the `metamaskbot` PR
comment.

## **Screenshots/Recordings**

N/A

## **Pre-merge author checklist**

- [x] I've followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask
Extension Coding
Standards](https://github.com/MetaMask/metamask-extension/blob/main/.github/guidelines/CODING_GUIDELINES.md).
- [x] I've completed the PR template to the best of my ability
- [x] I’ve included tests if applicable
- [x] I’ve documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [x] I’ve applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-extension/blob/main/.github/guidelines/LABELING_GUIDELINES.md)).
Not required for external contributors.

## **Pre-merge reviewer checklist**

- [ ] I've manually tested the PR (e.g. pull and build branch, run the
app, test code being changed).
- [ ] I confirm that this PR addresses all acceptance criteria described
in the ticket it closes and includes the necessary testing evidence such
as recordings and or screenshots.

development/metamaskbot-build-announce.js

@@ -144,9 +144,6 @@ async function start() {
   const bundleSizeDataUrl =
     'https://raw.githubusercontent.com/MetaMask/extension_bundlesize_stats/main/stats/bundle_size_data.json';
 
-  const coverageUrl = `${BUILD_LINK_BASE}/coverage/index.html`;
-  const coverageLink = `<a href="${coverageUrl}">Report</a>`;
-
   const storybookUrl = `${BUILD_LINK_BASE}/storybook/index.html`;
   const storybookLink = `<a href="${storybookUrl}">Storybook</a>`;
 
@@ -174,7 +171,6 @@ async function start() {
     `build viz: ${depVizLink}`,
     `mv3: ${bundleSizeStatsLink}`,
     `mv2: ${userActionsStatsLink}`,
-    `code coverage: ${coverageLink}`,
     `storybook: ${storybookLink}`,
     `typescript migration: ${tsMigrationDashboardLink}`,
     `<a href="${allArtifactsUrl}">all artifacts</a>`,