Fix #5214 good first issues link fixed under wiki/Installing-Oppia-Android.md

[AhzamAkhtar]

Explanation

Fix #5214 under this PR, the link has been correctly updated to good first issue This item is good for new contributors to make their pull request. from the wrong one, that is https://github.com/oppia/oppia-android/wiki/Oppia-Android-Testing in wiki/Installing-Oppia-Android.md under Next Steps Section.

Essential Checklist

• The PR title and explanation each start with "Fix #bugnum: " (If this PR fixes part of an issue, prefix the title with "Fix part of #bugnum: ...".)
• Any changes to scripts/assets files have their rationale included in the PR explanation.
• The PR follows the style guide.
• The PR does not contain any unnecessary code changes from Android Studio (reference).
• The PR is made from a branch that's not called "develop" and is up-to-date with "develop".
• The PR is assigned to the appropriate reviewers (reference).

[github-actions]

Hi! @AhzamAkhtar Welcome to Oppia! Could you please follow the instructions here and sign the CLA Sheet to get started? You'll need to do this before we can accept your PR. Thanks!

[adhiamboperes]

Closing as this is a small change and can be fixed as part of #5210