Closes #837: htaccess always modified when saving settings

[Miraeld]

Description

Fixes #837

Documentation

User documentation

The .htaccess was always being modified while saving Imagify settings.
This PR fix this behavior to modify the .htaccess only when there is a change in the settings.

Technical documentation

We just check if the previous value is the same as the current one before changing the .htaccess.

Type of change

Delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue).

Checklists

Feature validation

• I validated all the Acceptance Criteria. If possible, provide sreenshots or videos.
• I triggered all changed lines of code at least once without new errors/warnings/notices.

Documentation

• I prepared the user documentation for the feature/enhancement and shared it in the PR or the GitHub issue.
• The user documentation covers new/changed entry points (endpoints, WP hooks, configuration files, ...).
• I prepared the technical documentation if needed, and shared it in the PR or the GitHub issue.

Code style

• I wrote self-explanatory code about what it does.
• I wrote comments to explain why it does it.
• I named variables and functions explicitely.
• I protected entry points against unexpected inputs.
• I did not introduce unecessary complexity.
• I listed the introduced external dependencies explicitely on the PR.
• I validated the repo-specific guidelines from CONTRIBUTING.md.

[Mai-Saad]

Related test plan https://wpmediaqa.testrail.io/index.php?/runs/view/831&group_by=cases:section_id&group_order=asc

[Mai-Saad]

Working as expected
testrail-report-589.pdf