Stylistic cleanup post-Bootstrap update

A few minor cleanup issues should be attended to since the Bootstrap update:

• The CO Petitions index filter button needs attention (e.g. at /registry/co_petitions/index/co:2)
• We should add “align-items: center” to .co-grid .row in the enrollment flow select listing (e.g. at /registry/co_enrollment_flows/select/co:2)

Do a sweep of the UI and ensure clean up of these and any other trivial issues that may have come about during recent updates.