Fix #5267: Not able to navigate back from story. (#5278)

<!-- READ ME FIRST: Please fill in the explanation section below and
check off every point from the Essential Checklist! -->
## Explanation
<!--
- Explain what your PR does. If this PR fixes an existing bug, please
include
- "Fixes #bugnum:" in the explanation so that GitHub can auto-close the
issue
  - when this PR is merged.
  -->
Fixes #5267
Destroyed ExplorationActivity before creating TopicActivity to prevent
loop between the same two activity, when user tries to go back.

## Essential Checklist
<!-- Please tick the relevant boxes by putting an "x" in them. -->
- [x] 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: ...".)
- [x] Any changes to
[scripts/assets](https://github.com/oppia/oppia-android/tree/develop/scripts/assets)
files have their rationale included in the PR explanation.
- [ ] The PR follows the [style
guide](https://github.com/oppia/oppia-android/wiki/Coding-style-guide).
- [x] The PR does not contain any unnecessary code changes from Android
Studio
([reference](https://github.com/oppia/oppia-android/wiki/Guidance-on-submitting-a-PR#undo-unnecessary-changes)).
- [x] The PR is made from a branch that's **not** called "develop" and
is up-to-date with "develop".
- [x] The PR is **assigned** to the appropriate reviewers
([reference](https://github.com/oppia/oppia-android/wiki/Guidance-on-submitting-a-PR#clarification-regarding-assignees-and-reviewers-section)).

## For UI-specific PRs only
## Before

[no_way_home.webm](https://github.com/oppia/oppia-android/assets/76042077/8c2afa69-9237-4f0d-8b53-f1e89851bd4a)

## After

[home_coming.webm](https://github.com/oppia/oppia-android/assets/76042077/92e3bc79-b042-4610-bed5-def7dda2da2c)

<!-- Delete these section if this PR does not include UI-related
changes. -->
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](https://github.com/oppia/oppia-android/wiki/RTL-Guidelines))
- Add a video showing the full UX flow with a screen reader enabled (see
[accessibility
guide](https://github.com/oppia/oppia-android/wiki/Accessibility-A11y-Guide))
- For PRs introducing new UI elements or color changes, both light and
dark mode screenshots must be included
- Add a screenshot demonstrating that you ran affected Espresso tests
locally & that they're passing

---------

Co-authored-by: Adhiambo Peres <[email protected]>

app/src/main/java/org/oppia/android/app/player/exploration/ExplorationActivityPresenter.kt

@@ -397,6 +397,7 @@ class ExplorationActivityPresenter @Inject constructor(
         activity.startActivity(
           TopicActivity.createTopicActivityIntent(context, profileId.internalId, topicId)
         )
+        activity.finish()
       }
     }
   }