Fix #4285 by recreating ExplorationFragment with the newly updated te…

[KevinGitonga]

Explanation

Fixes #4285

This PR fixes issue whereby changes in text size as described here #4285 are
not reflected immediately once the user navigates back to previous page. I have updated ExplorationActivity and ExplorationPresenter to recreate ExplorationFragment when user resumes from OptionsActivity with the newly updated text size.

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

Before changes demo video

text_size_issue_bfr_demo.mp4

After changes demo video

text_size_issue_after_demo.mp4

[BenHenning]

See #4285 (comment). It may be worth waiting until #4411 is merged before proceeding with this PR since I'm expecting that PR to fully address #4285.

[KevinGitonga]

Closing this PR since another PR #4411 will fix this issue once merged into the codebase.