fix: wrap meaningful icons with text to improve screen reader output

[arbirali]

Description

On the Discussions page, screen reader–only text has been added to icons without labels, and aria-hidden="true" has been applied to icons that already have visible text.

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Steps to reproduce:

• Open the page: [Posts Page](https://apps.sandbox.openedx.edly.io/discussions/course-v1:OpenedX+DemoX+DemoCourse/posts)
• Select either "My Posts", "All Posts", or "Learners".
• Access the like and star icon.
• Notice that overall, many of the icons are missing the descriptive text.

Related to overhangio/tutor-indigo#146

How Has This Been Tested?

I set up Tutor locally with the Indigo plugin enabled (enabled by default) and followed the steps above to reproduce the issue. By inspecting the frontend HTML, I identified the required adjustment. After applying the fix, keyboard navigation using the Tab key now works correctly for both selected and non-selected options.

Screenshots/sandbox (optional):

Sandbox Link
Taiga Ticket (If someone have access)

Merge Checklist

• If your update includes visual changes, have they been reviewed by a designer? Send them a link to the Sandbox, if applicable.
• Is there adequate test coverage for your changes?

Post-merge Checklist

• Deploy the changes to prod after verifying on stage or ask @openedx/edx-infinity to do it.
• 🎉 🙌 Celebrate! Thanks for your contribution.

[awais-ansari]

Please update the test cases. The required checks are failing. Other than that, the changes look good to me.

[wittjeff]

Please post examples of the new text "visible" to screen reader users with this change in place.