[SDK-3646] Reliability and performance improvements to CookieStore

[evansims]

Changes

This PR:

• Addresses an issue where encrypted cookies could sometimes become corrupted under certain circumstances, due to an encoding issue introduced by the encryption process. In these circumstances, this would result in a user being seemingly randomly logged out, or potentially failing the state check during authentication flows.
• Adds a flagging process to track mutations to the session state, to avoid sending unnecessary headers.
• Addresses an issue where if a cookie domain was assigned the same value as the HTTP_HOST environment variable the domain property in the cookie header could be sent improperly formatted.

Note that these changes require structural changes to session cookies. Upon updating your application with these merged changes, some users may need to reauthenticate to replace old session cookies with the new format.

This PR also contains unrelated changes to address failing unit tests necessary for this PR to pass review:

• Dependency 'phpstan/phpstan-strict-rules' has been pinned to 1.4.3 temporarily to work around a breaking change introduced upstream.

References

See internal ticket SDK-3646

Testing

• Tests have been adjusted to compensate for some of the internal API changes necessary for this fix
• See GitHub workflow results

Contributor Checklist

• I have read the Auth0 general contribution guidelines
• I have read the Auth0 code of conduct

[codecov-commenter]

Codecov Report

Base: 100.00% // Head: 100.00% // No change to project coverage 👍

Coverage data is based on head (620235d) compared to base (1e34266).
Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

@@             Coverage Diff             @@
##                main      #649   +/-   ##
===========================================
  Coverage     100.00%   100.00%           
- Complexity       996      1006   +10     
===========================================
  Files             65        65           
  Lines           3636      3677   +41     
===========================================
+ Hits            3636      3677   +41     

Impacted Files	Coverage Δ
src/Store/CookieStore.php	100.00% <100.00%> (ø)

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report at Codecov.
📢 Do you have feedback about the report comment? Let us know in this issue.