Component-scope [cngxMatTabs] configuration. Returns a
Provider[] so the result can be spread into a component's
providers or viewProviders (which cannot accept opaque
environment providers).
Merges over the outer config (via skipSelf), so a component-scope
call refines the root provideMatTabsConfig instead of
reverting its untouched keys to library defaults - only the keys
the local features set are overridden for the subtree.