Remove temporary packages/kbn-ui-framework eslint overrides

[spalger]

In order to move forward with #49244 we needed to disable some rules in packages/kbn-ui-framework. We need to remove the related overrides and get the package passing these rules pretty soon.

// .eslintrc.js
{
  files: ['packages/kbn-ui-framework/**/*.{js,ts,tsx}'],
  rules: {
    'jsx-a11y/no-onchange': 'off',
  },
},

[timroes]

Since we're planning to get rid of this as soon as possible, I think we should not spend any effort fixing linting rules here anymore. So I would close this.