MM-4887: Remove back to MM button for Zapier-MM OAuth integration setup (#13890)

* MM-4887: Remove back to MM button got Zapier OAuth setup

* MM-4887: remove Zapier dependency

Co-authored-by: Catalin Tomai <catalin.tomai@mattermost.com>

web/oauth.go

@@ -117,7 +117,11 @@ func authorizeOAuthPage(c *Context, w http.ResponseWriter, r *http.Request) {
 	loginHint := r.URL.Query().Get("login_hint")
 
 	if err := authRequest.IsValid(); err != nil {
-		utils.RenderWebAppError(c.App.Config(), w, r, err, c.App.AsymmetricSigningKey())
+		utils.RenderWebError(c.App.Config(), w, r, err.StatusCode,
+			url.Values{
+				"type":    []string{"oauth_invalid_param"},
+				"message": []string{err.Message},
+			}, c.App.AsymmetricSigningKey())
 		return
 	}