(1) In uncontested divorce suits, corroboration of the plaintiff's grounds for divorce shall not be necessary or required.
(2) In contested suits, corroboration of the injured party's grounds may be expressly waived in writing by the other spouse.
(3) This section does not apply to proof as to residence, which must be corroborated, and does not apply to proof of separation and continuity of separation without cohabitation, which must be corroborated.
(4) In uncontested cases, proof as to residence and proof of separation and continuity of separation without cohabitation may be corroborated by either oral testimony or verified affidavit of persons other than the parties.