Fixes #3569 Merged promoted_story_list.xml files

[mukulasija]

Fixes #3569 Merged 4 promoted_story_list.xml files into single xml file

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).

For UI-specific PRs only

If your PR includes UI-related changes, then:

• Add screenshots for portrait/landscape for both a tablet & phone of the before & after UI changes
• For the screenshots above, include both English and pseudo-localized (RTL) screenshots (see RTL guide)
• Add a video showing the full UX flow with a screen reader enabled (see accessibility guide)
• Add a screenshot demonstrating that you ran affected Espresso tests locally & that they're passing

[mukulasija]

@rishidyno PTAL

[rishidyno]

LGTM @mukulasija.

[rt4914]

LGTM @mukulasija.

Thanks @rishidyno for reviewing this.

[rt4914]

@mukulasija Thanks. PTAL at comments.

[oppiabot]

Hi @mukulasija, I'm going to mark this PR as stale because it hasn't had any updates for 7 days. If no further activity occurs within 7 days, it will be automatically closed so that others can take up the issue.
If you are still working on this PR, please make a follow-up commit within 3 days (and submit it for review, if applicable). Please also let us know if you are stuck so we can help you!

[Arjupta]

@mukulasija always remeber to ask for a review if you have replied with a question to any comments so that the reviewer can answer them.

[rt4914]

LGTM, thanks.