Media Library Bulk Select button size should be smaller

[afercia]

In the Media Library grid, the Bulk Select button is larger than default ones and a bit misaligned. See the screenshot below, compared with the button in the list mode which is perfectly aligned with other elements.

wp.media.view.Button has a large size by default but in some cases it should be set to the default size.

[afercia]

The proposed patch tries to set the correct size for the Bulk Select button. Please see also #32324 maybe the two patches should be merged.

Not sure this is the best way to fix the button size, it's the only one I could think of :) in the edit view the button has now the default size, while in the select view the "Cancel Selection" and "Delete Selected" buttons are still "large". Also, tried to avoid a small "jump" of the grid caused by the toolbar different height when toggling edit/select modes.

[wonderboymusic]

In 32862:

Media Library Bulk Select button size should be smaller.

Props afercia.
Fixes #32325.