MDL-45843 mod_lti: Updated custom parameters test

Updated test_split_custom_parameters to include new function parameters
Corrected PHPdoc entry for lti_split_custom_parameters
Fixed incorrect line separators in ltiservice.php
Revert "MDL-45843 mod_lti: Updated custom parameters test"

This reverts commit d546819bffb1074ea516a0af1f35c75a69b9c3b4.
MDL-45843 mod_lti: Update custom parameter test

Updated test_split_custom_parameters function to include new parameters
for lti_split_custom_parameters method
Corrected PHPdoc for lti_split_custom_parameters and lti_get_ims_role
methods
Fixed incorrect line separator in ltiservice.php