[TASK] Remove reference to old tx_templavoila nesting tag

This change removes a reference to the old <tx_templavoila>
nesting tag which was switched away from in TYPO3 4.7, making
section objects inside sections in flexforms, use the proper
array index path "title" instead of "tx_templavoila.title".

Releases: 6.2
Resolves: #54503
Change-Id: I4c975cf4eed127ca90ead3d7566fbc826f5b78db
Reviewed-on: https://review.typo3.org/26482
Reviewed-by: Wouter Wolters
Reviewed-by: Fabien Udriot
Reviewed-by: Dmitry Dulepov
Tested-by: Wouter Wolters
Reviewed-by: Markus Klein
Tested-by: Markus Klein