fix(rds): DBCluster controller not recognizing changes in VpcSecurityGroups

[schroeder-paul]

Description of your changes

The controller does not pick up the following difference and rectifies ist:

apiVersion: rds.aws.crossplane.io/v1alpha1
kind: DBCluster
metadata:
  ...
spec:
  forProvider:
    ...
    vpcSecurityGroupIDs:
      - sg-0ea3574b267cb293c                <=== does not match the one from below
...
status:
  atProvider:
    ...
    vpcSecurityGroups:
      - status: active
        vpcSecurityGroupID: sg-563ab33d     <=== dose not match the one from above
  conditions:
    - lastTransitionTime: "2022-11-17T16:53:44Z"
      reason: Available
      status: "True"
      type: Ready
    - lastTransitionTime: "2022-11-17T16:51:42Z"
      reason: ReconcileSuccess
      status: "True"
      type: Synced

I have:

• Read and followed Crossplane's [contribution process].
• Run make reviewable test to ensure this PR is ready for review.

How has this code been tested

See added tests.

[MisterMX]

LGTM. Thanks for the fix @schroeder-paul!