[stable12] Better result handling of email search

[nickvergessen]

The limit of the response should be respected

Fixnextcloud/spreed#617

Master/stable13 needs a different patch (collaboration rewrite) but will come soon.

[codecov]

Codecov Report

Merging #8205 into stable12 will decrease coverage by 0.03%.
The diff coverage is 25%.

@@ Coverage Diff @@## stable12 #8205 +/- ##
==============================================
- Coverage 53.84% 53.81% -0.04% - Complexity 22755 22758 +3 
==============================================
Files 1386 1386 Lines 87129 87180 +51 Branches 1331 1331 ==============================================
- Hits 46914 46913 -1 - Misses 40215 40267 +52

Impacted Files	Coverage Δ	Complexity Δ
...es_sharing/lib/Controller/ShareesAPIController.php	56.59% <25%> (-6.65%)	121 <0> (+3)
core/js/js.js	61.27% <0%> (-0.56%)	0% <0%> (ø)
lib/private/Files/Cache/Propagator.php	96.2% <0%> (+1.26%)	16% <0%> (ø)	⬇️