[8.4](backport #1130) Remove the fleet reporter

[mergify]

This is an automatic backport of pull request #1130 done by Mergify.
Cherry-pick of 6e2e06c has failed:

On branch mergify/bp/8.4/pr-1130
Your branch is up to date with 'origin/8.4'.

You are currently cherry-picking commit 6e2e06c06.
  (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:   CHANGELOG.next.asciidoc
	modified:   internal/pkg/agent/application/gateway/fleet/fleet_gateway.go
	modified:   internal/pkg/agent/application/gateway/fleet/fleet_gateway_test.go
	modified:   internal/pkg/agent/application/managed_mode.go
	modified:   internal/pkg/agent/configuration/fleet.go
	modified:   internal/pkg/fleetapi/checkin_cmd.go
	deleted:    internal/pkg/reporter/fleet/config/config.go
	deleted:    internal/pkg/reporter/fleet/reporter_test.go

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by them: internal/pkg/reporter/fleet/reporter.go

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

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• Start Time: 2022-09-09T15:50:03.429+0000

• Duration: 15 min 15 sec

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Passed	6109
Skipped	23
Total	6132

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🌐 Coverage report

Name	Metrics % (covered/total)	Diff
Packages	97.222% (70/72)	👎 -0.038
Files	67.713% (151/223)	👎 -0.144
Classes	68.172% (302/443)	👍 0.01
Methods	51.782% (828/1599)	👎 -0.049
Lines	38.164% (9025/23648)	👎 -0.114
Conditionals	100.0% (0/0)	💚