[BUGFIX] Avoid unnecessary nesting in typo3-mfa-totp-url-info-button

The web component should behave like a button, there is no need
to have another button nested inside. In addition we remove the
usage of native attributes for custom properties to avoid unintended
side effects.

Resolves: #100453
Releases: main
Change-Id: I2c5644144f545e7740dfc6bbf093d3ef00c26339
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/78468


Tested-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>