[FOLLOWUP] Remove SET prefix from checkbox name

Setting module data does no longer use the "SET"
prefix. This adjusts one place, where the migration
was not done yet.

Note: This has no functional impact, since the checkbox
is handled via JavaScript and not in a POST request.

Resolves: #96895
Releases: main
Change-Id: Ie0feb1218ccb089df9164eafd7241be56c2b7421
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/73531


Tested-by: core-ci <typo3@b13.com>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Oliver Bartsch <bo@cedev.de>

typo3/sysext/backend/Resources/Private/Templates/PageLayout/PageModule.html

@@ -49,7 +49,7 @@
                 type="checkbox"
                 id="checkShowHidden"
                 class="form-check-input"
-                name="SET[showHidden]"
+                name="showHidden"
                 value="1"
                 {f:if(condition:'{hiddenElementsState} == 1', then:'checked="checked"')}
             />