For #12600 - remove AddonInstalled event when the permission dialog is shown

[jhugman]

This was spotted by @csadilek, reviewing #12136.

Tests are difficult, but scheduled in #11210 (linking this to keep it in mind when doing those tests).

Pull Request checklist

• Tests: This PR includes thorough tests or an explanation of why it does not
• Screenshots: This PR includes screenshots or GIFs of the changes made or an explanation of why it does not
• Accessibility: The code in this PR follows accessibility best practices or does not include any user facing features. In addition, it includes a screenshot of a successful accessibility scan to ensure no new defects are added to the product.

After merge

• Milestone: Make sure issues finished by this pull request are added to the milestone of the version currently in development.

To download an APK when reviewing a PR:

1. click on Show All Checks,
2. click Details next to "Taskcluster (pull_request)" after it appears and then finishes with a green checkmark,
3. click on the "Fenix - assemble" task, then click "Run Artifacts".
4. the APK links should be on the left side of the screen, named for each CPU architecture

[csadilek]

👍

[codecov-commenter]

Codecov Report

Merging #12601 into master will decrease coverage by 0.00%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master   #12601      +/-   ##
============================================
- Coverage     25.15%   25.14%   -0.01%     
  Complexity      845      845              
============================================
  Files           389      389              
  Lines         15700    15702       +2     
  Branches       2022     2023       +1     
============================================
  Hits           3949     3949              
- Misses        11444    11446       +2     
  Partials        307      307              

Impacted Files	Coverage Δ	Complexity Δ
...g/mozilla/fenix/addons/AddonsManagementFragment.kt	0.00% <ø> (ø)	0.00 <0.00> (ø)
...src/main/java/org/mozilla/fenix/components/Core.kt	25.68% <0.00%> (-0.73%)	1.00% <0.00%> (ø%)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update fb1d7e1...19da0ce. Read the comment docs.