fix rds connection secret move to observe and fix issue in dbinstance

[haarchri]

Signed-off-by: haarchri [email protected]

Description of your changes

• change connectionDetails from postCreate to postObserve - because connectionDetails not published from time to time

• fix issue in db-instance if instance is a cluster-member

  Warning  CannotUpdateExternalResource  5m14s (x22 over 19m)  managed/dbinstance.rds.aws.crossplane.io  cannot update DBInstance in AWS: InvalidParameterCombination: The specified DB instance is a member of a DB cluster. Storage grows based on usage. You don't need to set it explicitly.
           status code: 400, request id:

Fixes #1169 #776

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

rollout rds-cluster & rds-instance and checked the secrets

NAME                                                           READY   SYNCED   EXTERNAL-NAME
dbcluster.rds.aws.crossplane.io/example-aurora-mysql-cluster   True    True     example-aurora-mysql-cluster

NAME                                                             READY   SYNCED   EXTERNAL-NAME
dbinstance.rds.aws.crossplane.io/example-aurora-mysql-instance   True    True     example-aurora-mysql-instance

NAME                             TYPE                                  DATA   AGE
example-aurora-mysql-cluster     connection.crossplane.io/v1alpha1     3      25m
example-aurora-mysql-instance    connection.crossplane.io/v1alpha1     3      25m

 kubectl describe secrets example-aurora-mysql-cluster -n default                
Name:         example-aurora-mysql-cluster
Namespace:    default
Labels:       <none>
Annotations:  <none>

Type:  connection.crossplane.io/v1alpha1

Data
====
endpoint:  77 bytes
password:  16 bytes
username:  5 bytes

kubectl describe secrets example-aurora-mysql-instance -n default
Name:         example-aurora-mysql-instance
Namespace:    default
Labels:       <none>
Annotations:  <none>

Type:  connection.crossplane.io/v1alpha1

Data
====
endpoint:  70 bytes
port:      4 bytes
username:  5 bytes

[haarchri]

Please Note we will release this PR with v0.26.0 If we have a need we can Backport to v0.25.0