chore: update phpstan version and remove phpstan-baseline

This commit updates the version of phpstan specified in .phive/phars.xml file to 1.* and the current installed version to 1.12.13.

Additionally, it removes all the previously ignored errors in phpstan-baseline.neon. The actions were taken possibly due to fixes to these errors or related update in the codebase causing them to be obsolete.

Please ensure related checks/errors do not surface again due to the removed baseline ignores.

.phive/phars.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <phive xmlns="https://phar.io/phive">
-  <phar name="phpstan" version="1.11.8" installed="1.11.8" location="./tools/phpstan" copy="false"/>
+  <phar name="phpstan" version="1.*" installed="1.12.13" location="./tools/phpstan" copy="false"/>
   <phar name="phpunit" version="^10.5.20" installed="10.5.20" location="./tools/phpunit" copy="false"/>
   <phar name="phpcs" version="^3.10.1" installed="3.10.1" location="./tools/phpcs" copy="false"/>
   <phar name="phpcbf" version="^3.10.1" installed="3.10.1" location="./tools/phpcbf" copy="false"/>