[Issue] Prevent product gallery elements from blinking when they load

This issue is automatically created based on existing pull request: #27871: Prevent product gallery elements from blinking when they load

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Description (*)

In this PR I would like to improve the loading experience of the gallery on product page. On the attached screenshot you can see that there are small periods of time when:

1. Product image disappears and there is a white space until gallery initializes and its images load.
2. Left arrow is shown and then hidden after gallery loads.

Preconditions (*)

Steps to reproduce (*)

1. Gallery placeholder image is positioned properly (as before) on all supported browsers and resolutions.
2. Gallery works as before when initialized.

Actual result (*)

Expected result (*)

Note: There is a loader shown properly for a few frames, it just didn't get captured on the gif.