[BUGFIX] Prevent bootstrap from removing empty csh popover content

Since bootstrap v5.0.2 the popover module removes empty title and
content html nodes. This plays however against our strategy to load csh
text on demand. To prevent the automatic removal, an empty p-tag is set
in the data-bs-content attribute.

In addition this fixes another two small bugs:
1. Remove the unexpected argument in the setContent method.
2. Add a new update method in Popover to update the arrow position after
fetching csh text.

Resolves: #94482
Releases: master
Change-Id: I70ba510b793e10fa6b096d9f8bf54ccf1a823a19
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/69719


Tested-by: core-ci <typo3@b13.com>
Tested-by: Riccardo De Contardi <erredeco@gmail.com>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Benni Mack <benni@typo3.org>