Fixes upload buttons not showing up

[omarkasem]

• Implements https://github.com/GravityKit/GravityView/issues/2208
• The main issue was gform_basic was loaded before gform_admin_icons
• I tried to reverse the order of the enqueue but that can't be done as gform_basic is not loaded with enqueue and it caused some style issues
• So i added an override style using gform_theme which only loads when 2.5 style theme is chosen and it's only loaded also if gf is 2.9 or more

💾 Build file (cf9276ee2).