[uicfg] Fix autoform_section rtags wrt derivation cw 3.25 introduced the 'derived rtags' feature, but missed that `autoform_section` implementation was overriding several methods where this was implemented in the base class. The following problems are tested and fixed: * during init, we should not attempt to call `_initfunc_step2` if there is some parent, * but we should handle expansion of wildcard ('*' used as subject or object of a tag) since this is handled during init step for this class, unlike others which handle this in `get` method (i.e. at lookup time), * fix overrided `get` method to consider parent rtag if any. Closes #17107020

Twisted < 16.0.0
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