Revert improve analytics dashboards schema errors

What does this MR do and why?

Revert "Merge branch '444915-improve-schema-errors-with-custom-validation' into 'master'"

This reverts merge request !153152 (merged) which caused all existing and new custom analytics dashboards to display errors as mentioned here !153152 (comment 1915991757).

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

Before	After

How to set up and validate locally

1. Follow these instructions to enable product analytics & analytics dashboards on your GDK.
2. Go to Project > Analytics > Analytics dashboards and click on the alert button to configure custom dashboards.
3. Select a custom dashboard project and click save.
4. Go back to Project > Analytics > Analytics dashboards and click on New dashboard and create one.
   • If you have no visualizations to select from, then you'll either need to fully set up product analytics to make its prebuilt visualizations available or add your own custom one for which I've attached a snippet below that you can add to your custom dashboard project's repository.
5. Save the custom dashboard and view the dashboard and dashboards list.

# .gitlab/analytics/dashboards/visualizations/viz.yaml
version: 1
type: LineChart
data:
  type: cube_analytics
options:
  xAxis:
    name: Time
    type: time
  yAxis:
    name: Counts
    type: value