Annexation or incorporation by a municipal corporation or other unit of local government does not affect the right of an electric supplier to continue or extend electric service within its certified territory except insofar as that right is affected or modified by Article XVIII or any other article of the Ohio Constitution. Notwithstanding this section or any other provision of law, the right of a municipal corporation to furnish service to such portion of the corporation as has been annexed to the corporation since the time maps have been drawn in accordance with section 4933.82 of the Revised Code shall not be abridged.