Add banner for Prom exporter vs Collector receiver survey

[ArthurSens]

Adds a banner promoting the survey we're doing in collaboration with OTel's End User SIG.

Here's the link for the doc we're using to organize the survey: https://docs.google.com/document/d/1gfE8UmeHaAmFG6ZjRiVDO2Phi-5Vk3mLpMU3YJQ58PU/edit?tab=t.0#heading=h.zbk80121fq6r

Leaving this as a draft until we have the sibling PR opened in OTel's website :)

[ArthurSens]

@juliusv @jan--f , OTel is publishing this survey later today and keeping their banner up for 1 month.

Are we ok with this timeline as well? I'd love to publish this rather sooner than later, but the amount of time we keep this up can definitely be discussed!

[AndrejKiri]

Thank you @ArthurSens for creating the banner! 🙌 I suggested a few changes.

Please, wait with merging until I get 👍 from OTel End-user SIG (should happen later today).

[juliusv]

Fine with me besides my comments :)

[ArthurSens]

The survey was released in the OTel website and I just now realized the CI failures here 😅

They don't seem related to this PR though

[ArthurSens]

@juliusv I've spent some time debugging this but this goes beyond my front-end skills 😭

The error I'm seeing in CI is

2:40:57 PM:    Generating static pages (0/573) ...
2:41:02 PM: Error occurred prerendering page "/docs/prometheus/3.3/querying/remote_read_api". Read more: https://nextjs.org/docs/messages/prerender-error
2:41:02 PM: TypeError: Cannot read properties of undefined (reading 'className')
2:41:02 PM:     at <unknown> (.next/server/chunks/354.js:4:75563) {
2:41:02 PM:   digest: '50886101'
2:41:02 PM: }
2:41:02 PM: Export encountered an error on /docs/[...slug]/page: /docs/prometheus/3.3/querying/remote_read_api, exiting the build.
2:41:02 PM:  ⨯ Next.js build worker exited with code: 1 and signal: null

To me, it's really weird that we're failing to render a page from 3.3. I don't see how we're only seeing this fail now. Could you help me out on this one?