Plugin E2E: Use new e2e selectors

[sunker]

What this PR does / why we need it:

This PR replaces a few unsafe locators with proper selectors defined grafana/e2e-selectors (and in the versioned selectors in plugin-e2e). The new selectors where recently added to the main branch of Grafana, hence we'll have to use the unsafe locator for versions before 11. This should be fine though as no one will ever backport selector updates to older version of Grafana.

Also updating related docs.

Which issue(s) this PR fixes:

Fixes https://github.com/grafana/plugin-tools/issues/724

Special notes for your reviewer: The selectors were added to Grafana in the following PRs.

https://github.com/grafana/grafana/pull/83248 https://github.com/grafana/grafana/pull/83246 https://github.com/grafana/grafana/pull/83240 https://github.com/grafana/grafana/pull/83230

📦 Published PR as canary version: Canary Versions

:sparkles: Test out this PR locally via: ```bash npm install @grafana/create-plugin@4.3.0-canary.833.13a3f6f.0 npm install @grafana/plugin-e2e@0.23.0-canary.833.13a3f6f.0 # or yarn add @grafana/create-plugin@4.3.0-canary.833.13a3f6f.0 yarn add @grafana/plugin-e2e@0.23.0-canary.833.13a3f6f.0 ```

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[grafana-plugins-platform-bot[bot]]

:rocket: PR was released in @grafana/create-plugin@4.4.0, @grafana/plugin-e2e@0.24.0 :rocket: