Fix LDAP Background Sync does not reset offset

[blizzz]

As observed on our instance… issue was that it was reported that more results are expected, while the count was already below the requested limit.

[codecov]

Codecov Report

Merging #7713 into master will increase coverage by 0.05%.
The diff coverage is 24.39%.

@@ Coverage Diff @@## master #7713 +/- ##
============================================
+ Coverage 51.18% 51.23% +0.05% - Complexity 24948 24954 +6 
============================================
Files 1605 1607 +2 Lines 94923 94957 +34 Branches 1376 1376 ============================================
+ Hits 48583 48652 +69 + Misses 46340 46305 -35

Impacted Files	Coverage Δ	Complexity Δ
...ps/user_ldap/composer/composer/autoload_static.php	0% <ø> (ø)	1 <0> (ø)	⬇️
apps/user_ldap/lib/ConnectionFactory.php	0% <0%> (ø)	2 <2> (?)
apps/user_ldap/lib/AccessFactory.php	0% <0%> (ø)	2 <2> (?)
.../user_ldap/composer/composer/autoload_classmap.php	0% <0%> (ø)	0 <0> (ø)	⬇️
apps/user_ldap/lib/Jobs/Sync.php	64% <52.63%> (+37.61%)	46 <9> (+2)	⬆️

[blizzz]

I added several more tests, and fixed one issue with that.

On our instance I see that the offset is not being reset, this should have been fixed though, but isn't. New addition is about rotating the prefix which does not apply to us.