fix: add pre-check on scheduler statefulset before patch it

[ShuangMen]

Description

add a pre-check before patch scheduler statefulset during kubecf upgrade.

Motivation and Context

#1675

How Has This Been Tested?

This has been tested in kubecf v2.7.1, re-run helm upgrade, no incorrect patch to scheduler statefulsets.

$ k get pod -n kubecf
NAME                                     READY   STATUS      RESTARTS   AGE
api-z0-0                                 17/17   Running     16         3h49m
api-z1-0                                 17/17   Running     16         3h49m
auctioneer-0                             6/6     Running     1          3h50m
cc-worker-z0-0                           6/6     Running     0          3h49m
cc-worker-z1-0                           6/6     Running     0          3h50m
cf-apps-dns-59f9f659f5-c4z5g             1/1     Running     0          3h54m
coredns-quarks-6db68476bd-4pjvh          1/1     Running     0          4h42m
coredns-quarks-6db68476bd-cdqtm          1/1     Running     0          4h42m
database-0                               2/2     Running     0          3h53m
database-seeder-10807f69f53c6e0f-hpxmr   0/2     Completed   0          2d
database-seeder-7a19efc54ebbb714-pqtbg   0/2     Completed   0          48d
database-seeder-c400c55f793c774c-5ltcb   0/2     Completed   0          5h27m
database-seeder-d49344d80353dd73-gmljj   0/2     Completed   0          48d
database-seeder-e421e917deb27f22-mps4r   0/2     Completed   0          4h42m
diego-api-z0-0                           9/9     Running     2          3h49m
diego-api-z1-0                           9/9     Running     2          3h49m
diego-cell-z0-0                          12/12   Running     9          3h49m
diego-cell-z1-0                          12/12   Running     9          3h49m
doppler-z0-0                             6/6     Running     0          3h50m
doppler-z1-0                             6/6     Running     0          3h50m
ian-nsenter-10.240.64.24                 0/1     Completed   0          7d2h
log-api-z0-0                             9/9     Running     0          3h49m
log-api-z1-0                             9/9     Running     0          3h49m
log-cache-0                              10/10   Running     0          3h50m
nats-z0-0                                7/7     Running     0          3h50m
nats-z1-0                                7/7     Running     0          3h50m
router-z0-0                              7/7     Running     0          3h50m
router-z1-0                              7/7     Running     0          3h50m
scheduler-z0-0                           12/12   Running     1          13m
scheduler-z1-0                           12/12   Running     1          14m
singleton-blobstore-z0-0                 8/8     Running     0          3h50m
uaa-z0-0                                 8/8     Running     0          3h50m
uaa-z1-0                                 8/8     Running     0          3h50m

Screenshots (if appropriate):

Types of changes

• [ x] Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code has security implications.
• [ x] My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[ShuangMen]

@jandubois, for script remove-deployment-updater-readiness.sh, I find another bug. Could you review the code change ?

[jandubois]

@ShuangMen Can you please rebase this PR on the latest master branch?

There is some issue with the recent go-buildpack bump, and the image for it seems to have gotten lost.

This has been reverted on master already, so rebasing this PR should allow it to pass through CI.

[ShuangMen]

I've rebased this PR.