docs: clarify OTel collector usage in getting started guide

[Garvit-77]

Summary

Reformatting the architecture diagram
adding note in getting started

Fixes #3538

Checks

• [] My PR fulfills the Definition of Done of the corresponding issue and not more (or parts if the issue is separated
  into multiple PRs)
• I used descriptive commit messages to help reviewers understand my thought process
• I signed off all my commits according to the Developer Certificate of Origin (DCO)(
  see Contribution Guide)
• My PR title is formatted according to the semantic PR conventions described in
  the Contribution Guide
• My content follows the style guidelines of this project (YAMLLint, markdown-lint)
• I regenerated the auto-generated docs for Helm and the CRD documentation (if applicable)
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  from the Netlify deploy preview
• My changes result in all-green PR checks (first-time contributors need to ask a maintainer to approve their test runs)

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[mowies]

LGTM!