Fix UI issues for importers/exporters pages

[summer-cook]

Summary

There are several UI issues that make things on the importers/exporters pages inaccessible

• color of text is white on a white background

  • on tabs
  • on exported file dropdown on exporters page

• tabs do not work for collections & file sets on both importers/:id & exporters/:id pages

Problem area / current issue

Acceptance criteria

• text on importers & exporters pages is all legible
• tabs work correctly

[crisr15]

Are these necessary changes for the app to function? If not, can we save these until phase 2 for budget reasons.

[summer-cook]

Link colors were fixed in

• fix link colors and make spacing a little better for now #85

The tabs are broken in bootstrap version 3.4.1.
See this slack message for details - https://assaydepot.slack.com/archives/C0313NK7ACC/p1689367498906059
They are broken in the official bootstrap docs for this version as well here: https://getbootstrap.com/docs/3.4/components/#nav-tabs

A patch will need to be added to bulkrax proper and most likely hyku if they are using this same tab component. But that may need to be in phase 2 because it is a more in-depth task.

[summer-cook]

Related Bulkrax PR: samvera/bulkrax#836