[FIX] tabsets: Multiple nesting issues

• [FIX] tabsets: Multiple nesting issues

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• [FIX] tabsets: When more than one tab contains other tabs decrementing $tabset_index doesn't necessarily get you back to the right "parent" tabset, so use $smarty_tabset_name as the key instead. This fixes an issue with tracker_legacy_insert when using tabs section format (as TextArea fields now are in tabs also)

See merge request !5370 (merged)

(cherry picked from commit f7b13b7e)

5de5360b [FIX] tabsets: When more than one tab contains other tabs decrementing...

Co-authored-by: Jonny Bradley jmail@nospaces.net