Fix #1554: Center Play/Pause Button

[ajkapala21]

Fixes #1544 Adds a right margin of 4px to the player button class which successfully centers each icon (pause, play, or loading). Although a previous comment highlighted that each icon was off center by a varying amount, from my inspection they are all off by the same amount, so the same margin can be applied to all of them.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 72.05%. Comparing base (3764ff6) to head (7bf5b5f).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1589 +/- ## ======================================= Coverage 72.05% 72.05% ======================================= Files 362 362 Lines 6746 6746 Branches 498 498 ======================================= Hits 4861 4861 Misses 1478 1478 Partials 407 407 ```

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[nukeop]

Nice, thank you.