Fix #19137: Shift rte-modal's save button to outside translation box in translation review modal(Contributor dashboard )

[Felix-Mauyon]

Overview

1. This PR fixes #19137
2. The PR shifts rte-modal's save button to the outside of the translation box. This is to ensure that when users are in edit mode, they do not have to scroll down to save the changes for given translation while reviewing.

Essential Checklist

• [x] I have checked the "Files Changed" tab and confirmed that the changes are what I want to make.
• [x] The PR title starts with "Fix #bugnum: " or "Fix part of #bugnum: ...", followed by a short, clear summary of the changes.
• [x] I have assigned the correct reviewers to this PR (or will leave a comment with the phrase "@{{reviewer_username}} PTAL" if I can't assign them directly).

Proof that changes are correct

Before

After

[oppiabot[bot]]

Hi @Felix-Mauyon, can you complete the following:

1. The body of this PR is missing the proof that changes are correct section, please update it to include the section. Thanks!

[oppiabot[bot]]

Assigning @StephenYu2018 for the first pass review of this PR. Thanks!

[oppiabot[bot]]

Hi @Felix-Mauyon, this PR is ready to be merged. Please address any remaining comments prior to merging, and feel free to ask someone to merge your PR once the CI checks pass and you're happy with it. Thanks!

[Felix-Mauyon]

@seanlip Please can you merge the PR. All checks have been passed

[seanlip]

Done. Thanks and congratulations on your first contribution to Oppia, @Felix-Mauyon! :tada: