Change icon id of page move action buttons

[Darshan-upadhyay1110]

• change id of prev and next page option for better readability

Change-Id: I962a4b4f745d53e8b6e002e7d57edd83dd8bd303

• Resolves: #
• Target version: main

Summary

TODO

• ...

Checklist

• I have run make prettier-write and formatted the code.
• All commits have Change-Id
• I have run tests with make check
• I have issued make run and manually verified that everything looks okay
• Documentation (manuals or wiki) has been updated or is not required

[eszkadev]

some test code uses old id:
AssertionError: Timed out retrying after 10000ms: Expected to find element:#toolbar-down #next, but never found it. Queried from:

[eszkadev]

  1) Comment Scrolling
       switch to previous or next slide:
     AssertionError: Timed out retrying after 10000ms: Expected to find element: `#prev-button`, but never found it. Queried from:

              > cy.get(#coolframe, [object Object]).its(0.contentDocument, [object Object])
      at Context.eval (webpack://cypress_test/./support/index.js:174:0)


  │ Duration:     1 minute, 21 seconds                                                             │
  │ Spec Ran:     impress/annotation_spec.js