[stable26] fix(dav): expand recurrences when searching

[backportbot-nextcloud]

Backport of #40541

[st3iny]

Drone failure seem to be unrelated.

There was 1 failure:

1) Test\DB\QueryBuilder\FunctionBuilderTest::testConcatString with data set "2 columns: string real and int literal" (Closure Object (...))
Failed asserting that two strings are equal.
--- Expected
+++ Actual
@@ @@
-'12'
+'32'

/drone/src/tests/lib/DB/QueryBuilder/FunctionBuilderTest.php:62

[blizzz]

Drone failure seem to be unrelated.

There was 1 failure:

1) Test\DB\QueryBuilder\FunctionBuilderTest::testConcatString with data set "2 columns: string real and int literal" (Closure Object (...))
Failed asserting that two strings are equal.
--- Expected
+++ Actual
@@ @@
-'12'
+'32'

/drone/src/tests/lib/DB/QueryBuilder/FunctionBuilderTest.php:62

Went away with a re-run.