[8.16](backport #4318) Fix Logs Explorer naming in outdated docs

[mergify]

Description

Updated the Logs Explorer name in some outdated docs.

Documentation sets edited in this PR

Check all that apply.

• Stateful (docs/en/observability/*)
• Serverless (docs/en/serverless/*)
• Integrations Developer Guide (docs/en/integrations/*)
• None of the above

Follow-up tasks

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• This PR does not need to be ported to another doc set because:
  • The concepts in this PR only apply to one doc set (serverless or stateful)
  • The PR contains edits to both doc sets (serverless and stateful)

---

This is an automatic backport of pull request #4318 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 2579aca has failed:

On branch mergify/bp/8.16/pr-4318
Your branch is up to date with 'origin/8.16'.

You are currently cherry-picking commit 2579aca0.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   docs/en/observability/logs-ecs-application.asciidoc
	modified:   docs/en/observability/logs-plaintext.asciidoc

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	both modified:   docs/en/observability/logs-filter.asciidoc
	deleted by us:   docs/en/serverless/logging/view-and-monitor-logs.mdx

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

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