Lmendoa/pd 6016 - #2903

src/test.ts was configured as the karma main but contained only the
zone.js import and initTestEnvironment, without the require.context that
pulls in spec files. With a main set, the builder loads only that entry,
so ng test ran 1 test while 334 spec files sat unexecuted. The suite has
effectively been a no-op, which is how a regression can land in a file
that ships with tests.

Declare zone.js/testing alongside the existing polyfills and drop main,
which lets the builder discover specs from tsconfig.spec.json. Delete
test.ts, now unreachable, and drop it from the spec tsconfig files list.

Turning spec discovery back on surfaced six component specs that had
never run. They fail identically on 20.1.6, so none of this is fallout
from the upgrade; they simply rotted unobserved.

Most were missing TestBed imports for what their templates actually use:
MatFormField/MatInput for mat-form-field and the errorStateMatcher
binding, MatCard/MatCheckbox for the interstitial, ReactiveFormsModule
for [formGroup], and CUSTOM_ELEMENTS_SCHEMA where a template renders a
sibling app-* component. Real modules rather than NO_ERRORS_SCHEMA, so
the specs keep catching template errors.

Two specs stubbed FormBuilder with object literals that only looked like
form controls. They passed only because ReactiveFormsModule was absent
and the bindings were never evaluated; with the directives present they
have to be real, so use the actual FormBuilder. ShareEmailsDomains also
needed a record carrying emailDomains, since the component builds its
form inside a filtered subscription and an empty record left formGroup
bound to undefined.