In any suit, action or proceeding involving the validity or enforcement of or relating to any contract of the authority, the authority shall be conclusively deemed to have become established and authorized to transact business and exercise its powers hereunder upon proof of the adoption of a resolution of the governing body declaring the need for the authority. Such resolution shall be deemed sufficient if it declares that there is such need for an authority and finds in substantially the foregoing terms (no further detail being necessary) that either or both of the conditions enumerated in § 15.2-5305 exist in the city. A copy of such resolution duly certified by the clerk shall be admissible in evidence in any suit, action or proceeding.