Add Validate button in the ESPhome Builder add on in Home Assistant

**Describe the problem you have/What new integration you would like**

Add a Validate button or link to the code editor screen in the esphome builder add on in homeassistant.
this would be next to the save and install buttons in the upper right hand corner of the editor.

**Please describe your use case for this integration and alternatives you've tried:**

this way you can validate the code without having to upload or download and without backing out of the editor.

**Additional context**

Start by locating the ESPHome Builder add-on's code editor and the existing Save and Install controls. Determine how editor actions invoke validation, then verify that a Validate control can run without uploading or leaving the editor and that its result is visible to the user.

Written by the indexing model from the issue text.