Fix PHP 8.1 "implicit conversion from float to int" exception at QR Code creation for Multi-Factor Auth
Summary:
Since PHP 8.1, conversion from float to integer should be explicit:
https://wiki.php.net/rfc/implicit-float-int-deprecate
Always `round()` the value to be an integer.
Closes T16171
Test Plan:
* Go a bunch of times to http://phorge.localhost/settings/panel/multifactor/ and click through until a QR Code is being displayed. (I guess. As the issue does not always happen.)
* Scan QR Code and confirm setup by entering TOTP Code; seems to still work.
Reviewers: O1 Blessed Committers, avivey
Reviewed By: O1 Blessed Committers, avivey
Subscribers: tobiaswiese, valerio.bozzolan, Matthew, Cigaryno
Maniphest Tasks: T16171
Differential Revision: https://we.phorge.it/D26180