improve picker theming

Signed-off-by: Andy Scherzinger <info@andy-scherzinger.de>

app/src/main/java/com/owncloud/android/ui/activity/FolderPickerActivity.kt

@@ -361,7 +361,7 @@ open class FolderPickerActivity :
             if (this is FilePickerActivity) {
                 viewThemeUtils.material.colorMaterialButtonPrimaryFilled(mCancelBtn!!)
             } else {
-                mCancelBtn!!.setTextColor(themeColorUtils.primaryColor(this, true))
+                viewThemeUtils.material.colorMaterialButtonPrimaryOutlined(mCancelBtn!!)
             }
             mCancelBtn!!.setOnClickListener(this)
         }