feat: linkcodes and preauthsessionids should not use padding

[porcellus]

Summary of change

• linkCodes and preAuthSessionIds should not use padding (= signs)
• we should accept them with and without = signs

Related issues

• Issue reported on discord about some router clearing = signs from query params

Test Plan

• Added new test that removes all '=' signs from linkcodes and preauthsessionids and checks that it remains the same (plus it still works)
• Added new test that adds '=' signs to linkcodes and preauthsessionids and checks that it sign in still works.

Documentation changes

We can update some example data, but we do not document the format in detail

Checklist for important updates

• Changelog has been updated
  • If there are any db schema changes, mention those changes clearly
• coreDriverInterfaceSupported.json file has been updated (if needed)
• pluginInterfaceSupported.json file has been updated (if needed)
• Changes to the version if needed
  • In build.gradle
• If added a new paid feature, edit the getPaidFeatureStats function in FeatureFlag.java file
• Had installed and ran the pre-commit hook
• If there are new dependencies that have been added in build.gradle, please make sure to add them
  in implementationDependencies.json.
• Update function getValidFields in io/supertokens/config/CoreConfig.java if new aliases were added for any core config (similar to the access_token_signing_key_update_interval config alias).
• Issue this PR against the latest non released version branch.
  • To know which one it is, run find the latest released tag (git tag) in the format vX.Y.Z, and then find the
    latest branch (git branch --all) whose X.Y is greater than the latest released tag.
  • If no such branch exists, then create one from the latest released branch.
• If added a foreign key constraint on app_id_to_user_id table, make sure to delete from this table when deleting the user as well if deleteUserIdMappingToo is false.