Switch button style on License Compliance page to confirm to Pajamas updates

Why are we doing this work

Pajamas deprecated the following GlButton variants - success (green button), info, & warning. And should be replaced by the confirm variant (blue button).

Our license compliance page has one instances of the success style on the 'Add a license` button.

Reference epic at &2964

Relevant links

Non-functional requirements

• Documentation:
• Feature flag:
• Performance:
• Testing:

Implementation plan

1. Switch btn-success to btn-confirm on the Add a license button.