[Feature] Implement LoadingIndicator Component

NOTE: Needs #348 to be merged and a new assets package published before merging

Description of Change

Adds a LoadingIndicator component based on Figma design

Uses newly added loading_indicator icon added to the assets page
Regenerated the icon list using the handy new script
Animates rotation of the component using react native built in animations
Accepts text and optional children. text is required if no children are provided

components

Code reviewer validation:

General
- [x] PR is linked to ticket(s)
- [x] PR has changelog label applied if it's to be included in the changelog
- [x] Acceptance criteria:
  - All satisfied or
  - Documented reason for not being performed or
  - Split to separate ticket and ticket is linked by relevant AC(s)
- [x] Above PR sections adequately filled out
- [x] If any breaking changes, in accordance with the pre-1.0.0 versioning guidelines: a CU ticket has been created for the VA Mobile App detailing necessary adjustments with the package version that will be published by this ticket
Code
- [x] Tests are included if appropriate (or split to separate ticket)
- [x] New functions have proper TSDoc annotations

If changes warrant a new version per the versioning guidelines and the PR is approved and ready to merge: