Refactor full text functions optimizer tests to add coverage to all functions (#128611) (#128734)

(cherry picked from commit b6880808d5c8b0300f9a4507fa215e6a88d7828c)

# Conflicts:
#	x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/optimizer/LocalPhysicalPlanOptimizerTests.java