SE-3691 [LX-1723] Hide audio transcripts element if no transcripts

[samuelallan72]

This prevents confusion and buggy views when there are no transcripts, by hiding the transcripts view entirely if no transcripts to display.

(It also removes some trailing space...)

Test instructions:

• create an audio asset with no transcripts
• view and verify that the transcripts element/bar is hidden
• add transcripts to the audio asset
• save and verify correct operation of the transcripts element

Reviewers:

• [x] @eLRuLL