fixed cache issues on element index page

[vnali]

fixed https://github.com/ethercreative/tags/issues/21 and https://github.com/ethercreative/tags/issues/18

for custom element types, Craft manages and invalidates element index cache on adding or editing an element -i believe element index cache is related to 3.7.14-. but when you add or edit a tag via element index page or even tag field on entry page, Craft is not aware of this plugin's tag element type so this PR invalidate element type cache for this plugin on after save tag event

[rob-c-baker]

Hmmm. This looks like it would work for Craft 4.

[BAM-Dennis]

can this be pulled and published?