[BUGFIX] Search for terms having foreign relation

This patch fixes whenever searching for terms against a
field having a foreign relation. Example of TCA
for "sys_file":

"searchTerms" => "metadata.title"

Will search for "title" in table "sys_file_metadata"

Change-Id: Ie3bc5e8ba79971368d52f78b80839053659a2a94
Releases: 0.4.0
Resolves: #59086