Update colors for Demo Architecture to match website theme

[svrnm]

The mermaid based architecture diagram for the demo uses colors that do not match the colors of the website theme:

https://opentelemetry.io/docs/demo/architecture/

It would be great if someone would update the colors in the underlying mermaid definition to be in line with other graphics like https://opentelemetry.io/img/otel-diagram.svg or https://opentelemetry.io/img/waterfall-trace.svg

Here is where the colors are defined: https://github.com/open-telemetry/opentelemetry.io/blob/main/content/en/docs/demo/architecture.md?plain=1#L62

Special Note for Outreachy Contributors: if you want to work on this issue, please make sure that you have completed the small steps and at least one assigned issue as outlined here: #5290

[Tharanishwaran]

hi @svrnm can i work on this issue ?

[svrnm]

@Tharanishwaran we are currently running the participation phase for outreachy, and we need to reserve some good first issues for the participants. If you participate in outreachy please take a look in #5290, otherwise I can currently not assign this issue to you. When the participation phase ends, and this issue is still available, I am happy to assign it.

[Tharanishwaran]

Thank you @svrnm

[ladyami]

@svrnm can I work on this?

[svrnm]

@svrnm can I work on this?

Please complete #5399 first