feat(samples): Show splash while authenticating

[renefloor]

Submit a pull request

CLA

• I have signed the Stream CLA (required).
• The code changes follow best practices
• Code changes are tested (add some information if not applicable)

Description of the pull request

Currently when you load the app the 'choose user screen' is always shown, even though it forwards you very soon to the logged in screen. This PR replaces that with the splash screen if you start the app while already being logged in.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 3.31%. Comparing base (0b34d4b) to head (6fdbf43).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@          Coverage Diff          @@
##            main     #42   +/-   ##
=====================================
  Coverage   3.31%   3.31%           
=====================================
  Files        117     117           
  Lines       3139    3139           
=====================================
  Hits         104     104           
  Misses      3035    3035           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.