placement: fix the issue cannot create dict follower constraints (#47750)

[ti-chi-bot]

This is an automated cherry-pick of #47750

What problem does this PR solve?

Issue Number: close #47741
Problem Summary:

Minimal reproduce step

mysql> CREATE PLACEMENT POLICY ssd FOLLOWER_CONSTRAINTS="{+disk=ssd: 1}";
ERROR 1105 (HY000): label constraints with invalid REPLICAS: count of replicas in dict constrains is 1, but got 2: invalid FollowerConstraints

What is changed and how it works?

skip the checks.

Check List

Tests

• Unit test
• Integration test

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

None

[nolouch]

/retest-required

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2023-10-23 03:20:31.100645726 +0000 UTC m=+2232028.687755871: ☑️ agreed by nolouch.
• 2023-10-23 03:37:55.27498202 +0000 UTC m=+2233072.862092150: ☑️ agreed by CabinfeverB.

[nolouch]

ptal @xhebox

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: CabinfeverB, nolouch, xhebox

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [xhebox]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[nolouch]

/retest-required