Fix Failing Tests related to the create_new_player()

[Jagadeeshftw]

Description

The failure was due to using set_caller_address, which only sets the address for the current contract. Since these tests involve calling an external contract (game_action_system), the appropriate function to set the address is set_contract_address.

Related Issue(s)

Closes #185

Checklist:

• Read the contributing docs (if this is your first contribution)

• Verified this is not a duplicate of any existing pull request

• Performed a self-review of the code

• Rebased to the last commit of the target branch (or merged it into my branch)

• Linked the issues which this PR resolves

• Documented the changes in code (API docs will be generated automatically)

[co-lead]

Thanks for your PR @Jagadeeshftw. It will be reviewed shortly.

[Jagadeeshftw]

While testing for the USERNAME ALREADY CREATED error, it is important to use two different usernames for the same caller. If the same username is used for both calls, the error will be caught earlier by the USERNAME ALREADY TAKEN check, and the test will not cover the intended error scenario.

[0xibs]

While testing for the USERNAME ALREADY CREATED error, it is important to use two different usernames for the same caller. If the same username is used for both calls, the error will be caught earlier by the USERNAME ALREADY TAKEN check, and the test will not cover the intended error scenario.

The aim of panicking with USERNAME_ALREADY_CREATED error is to prevent players who have created their usernames from creating another username or updating the created username. While USERNAME ALREADY TAKEN is for new players who have not created username before and tries to create one that has already been taken