InfluxDB 2.0: There is a missing "DELETE" method for "/documents/templates/{templateID}" [area/api]

[bednar]

The DELETE method for /documents/templates/{templateID} should be defined as:

delete:
      tags:
        - Templates
      summary: Delete a template
      parameters:
        - $ref: '#/components/parameters/TraceSpan'
        - in: path
          name: templateID
          schema:
            type: string
          required: true
          description: ID of template to delete
      responses:
        '204':
          description: delete has been accepted
        '404':
          description: template not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Error"
        default:
          description: unexpected error
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Error"

introduced by #12382, cc @desa, @goller

[kelwang]

dup with #12824,