Fleet and Agent 9.0.7 release notes

[karenzone]

Docs release manager: @kosabogi
Tech Writer: @karenzone

Fleet and Agent release notes

• Elastic-agent PR: Changelog for 9.0.7 elastic-agent#9926

  • Forwardport to main: [main](backport #9926) Changelog for 9.0.7 elastic-agent#10031
  • Forwardport to 9.1: [9.1] (backport #9926) Changelog for 9.0.7 elastic-agent#10032

• Fleet-server PR: Update changelog for 9.0.7 fleet-server#5509

  • Forwardport to main: [main](backport #5509) Update changelog for 9.0.7 fleet-server#5524
  • Forwardport to 9.1: [9.1](backport #5509) Update changelog for 9.0.7 fleet-server#5525

• Add PR link to docs release issue: https://github.com/elastic/dev/issues/3281

• Verify that release notes PRs are forwardported to appropriate branches

Post release

• Known issue: Doc: Add known issue 9.0.7: Agent stuck on failed upgrade elastic-agent#10042