[FrameworkBundle][SecurityBundle] Remove inert "extended-type" tag attributes

The "form.type_extension" tag is read by FormPass as "extended_type", with an
underscore. The five PHP configs using "extended-type" therefore declared
nothing: findTaggedServiceIds() performs no hyphen normalization, so every one
of them already fell through to the getExtendedTypes() branch.

The hyphenated spelling came from the XML configs, where it was valid, and was
carried over mechanically when those were converted. There is no XML loader
left on this branch.

Most type extensions in the same files already tag without any attribute and
rely on getExtendedTypes(), so this aligns the remaining five with them. The
resolved extension map is unchanged.