Update cms_toolbars.py

[vrac10]

Description

Currently, the default argument list 'action_args' accumulates the data from previous executions. This pull request makes sure that the default argument always has an empty list as intended.

Fixes #535

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

• Calling the function again and testing it shows that the previous execution data isn't accumulated in the default
  parameter

Checklist:

• My code follows the style guidelines of this project
• I have not added a commit to any .db files as part of my pull request
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules

[botanicvelious]

@warthog9 what do you think?