[chore] Patch FE dependencies in preparation for security review

[brenodt]

Description

This PR does two main things:

• ensures all Flutter dependencies are up-to-date against at least the highest patched version - including security fixes for the Dependabot alerts:
  • https://github.com/qaul/qaul.net/security/dependabot/37
  • https://github.com/qaul/qaul.net/security/dependabot/36
  • https://github.com/qaul/qaul.net/security/dependabot/35
  • https://github.com/qaul/qaul.net/security/dependabot/34
  • https://github.com/qaul/qaul.net/security/dependabot/33
  • https://github.com/qaul/qaul.net/security/dependabot/32
• Fixes versions in pubspec so that they are more readable and clearly indicate the version used for the build, without the need to look at a lock file

This was made in preparation for the upcoming security review.