Remove side effects form TCA cache building
Files in Configuration/TCA/table_name.php are designed to only
introduce and define the TCA array of the given table.
It was never designed to change or override already introduced TCA.
This was however possible because the buildTca method uses
the global TCA array when assembling all arrays.
This possibility should be removed so that changing TCA
is only possible in ext_tables.php or the upcoming new
file as described in #57862