Remove direct call to is_string() from templates

- Address https://github.com/friendica/friendica/issues/12011#issuecomment-1523913027

view/templates/settings/addons/connector.tpl

@@ -9,7 +9,7 @@
 	<div class="clear"></div>
 {{if $submit}}
 	<div class="settings-submit-wrapper panel-footer">
-    {{if $submit|is_string}}
+    {{if $submit}}
 		<button type="submit" name="{{$connector}}-submit" class="btn btn-primary settings-submit" value="{{$submit}}">{{$submit}}</button>
     {{else}}
         {{$count = 1}}

view/templates/settings/addons/panel.tpl

@@ -8,7 +8,7 @@
 	{{$html nofilter}}
 {{if $submit}}
 	<div class="settings-submit-wrapper panel-footer">
-    {{if $submit|is_string}}
+    {{if $submit}}
 		<button type="submit" name="{{$addon}}-submit" class="btn btn-primary settings-submit" value="{{$submit}}">{{$submit}}</button>
     {{else}}
         {{$count = 1}}

view/theme/frio/templates/settings/addons/connector.tpl

@@ -11,7 +11,7 @@
 		</div>
 		<div class="panel-footer">
 {{if $submit}}
-    {{if $submit|is_string}}
+    {{if $submit}}
 			<button type="submit" name="{{$connector}}-submit" class="btn btn-primary settings-submit" value="{{$submit}}">{{$submit}}</button>
     {{else}}
         {{$count = 1}}

view/theme/frio/templates/settings/addons/panel.tpl

@@ -11,7 +11,7 @@
 		</div>
 		<div class="panel-footer">
 {{if $submit}}
-    {{if $submit|is_string}}
+    {{if $submit}}
 			<button type="submit" name="{{$addon}}-submit" class="btn btn-primary settings-submit" value="{{$submit}}">{{$submit}}</button>
     {{else}}
         {{$count = 1}}