Add/Edit Panel: Enable new DS picker toggle by default (#68380)

* Add Panel: Enable new DS picker and onboarding DS prompt

* Add e2e selectors

public/app/features/datasources/components/picker/DataSourceDropdown.tsx

@@ -5,6 +5,7 @@ import React, { useCallback, useEffect, useRef, useState } from 'react';
 import { usePopper } from 'react-popper';
 
 import { DataSourceInstanceSettings, GrafanaTheme2 } from '@grafana/data';
+import { selectors } from '@grafana/e2e-selectors';
 import { reportInteraction } from '@grafana/runtime';
 import { DataSourceJsonData } from '@grafana/schema';
 import { Button, Icon, Input, ModalsController, Portal, useStyles2 } from '@grafana/ui';
@@ -103,12 +104,13 @@ export function DataSourceDropdown(props: DataSourceDropdownProps) {
   const styles = useStyles2(getStylesDropdown);
 
   return (
-    <div className={styles.container}>
+    <div className={styles.container} data-testid={selectors.components.DataSourcePicker.container}>
       {/* This clickable div is just extending the clickable area on the input element to include the prefix and suffix. */}
       {/* eslint-disable-next-line jsx-a11y/click-events-have-key-events, jsx-a11y/no-static-element-interactions */}
       <div className={styles.trigger} onClick={openDropdown}>
         <Input
           className={inputHasFocus ? undefined : styles.input}
+          data-testid={selectors.components.DataSourcePicker.inputV2}
           prefix={
             filterTerm && isOpen ? (
               <DataSourceLogoPlaceHolder />