Resolve #3178875 "Non static method drupalcoreentityentitystorageinterfacedelete"
requested to merge issue/webform_dropzonejs-3178875:3178875-non-static-method-drupalcoreentityentitystorageinterfacedelete into 8.x-1.x
For D9 compatibility:
- Added Patch #4 and tweaked line 61 with NULL to avoid error;
- Also included noted fix from another relevant issue (https://www.drupal.org/project/webform_dropzonejs/issues/3223534) which prevented editing the webform to test this issue;