Revert "FOCUS-5337: Fix ParseAsFloatFieldSource.equals() (was casting to another copy/pasted class name) and add a test for it to QueryEqualityTest"

This reverts commit d57f732bd45f97e87fe5b844b02cb70c2bdf477e.
Revert "FOCUS-5337: add field value source that can parse the serialized string value as a float, for use with the LWS click_val field, e.g. 'float(click_val)'"

This reverts commit ba6db70ad26d873f74f5baeed55a210740447593.