Select: Portal select menu to document.body (#36398)

* ValueMappings: Force overflowing modal content to scroll

* ValueMappings: Update unit tests

* Select: Portal Select to document.body, close menu on scroll

* Select: Fix tests + apply updates from https://github.com/grafana/grafana/pull/32833

* ValueMappingsEditorModal: Revert to using selectEvent in the tests

* Select: Fix remaining unit tests

* Portal: Rewrite Portal as a functional component so we can use useTheme2

* Modal: Remove modal styles from this PR

* Update E2E tests

* More unit test fixes

* Select: Fix remaining E2E tests

* Select: Create util method to select an option in tests

e2e/suite1/specs/query-editor.spec.ts

@@ -12,9 +12,9 @@ e2e.scenario({
       .should('be.visible')
       .within(() => {
         e2e.components.Select.input().should('be.visible').click();
-
-        cy.contains('gdev-prometheus').scrollIntoView().should('be.visible').click();
       });
+
+    cy.contains('gdev-prometheus').scrollIntoView().should('be.visible').click();
     const queryText = 'http_requests_total';
 
     e2e.components.QueryField.container().should('be.visible').type(queryText).type('{backspace}');