"Clone from" button is adding scroll when text is too long

Issue Summary

This is reproducible on Data Center: Yes

Steps to Reproduce

1. Option 1
   1. Create a mirror with a long name like (ex. `Stash - Bitbucket Mirror - with a really long name`)
   2. Open clone dialog
   3. Select the new mirror
2. Option 2
   1. Modify the name of current selection through developer tools

Expected Results

Text overflow should be follow by ellipsis.

Actual Results

A a scrollbar appears blocking the name of the mirror.

Workaround

No workaround