Retry CRD updates on conflicts

[joelanford]

Description of the change:
Always retry CRD updates when conflicts occur.

Motivation for the change:
Conflicts are common in eventually consistent controllers. Reconciliation should be tolerant to conflicts and retry updates with a backoff in the face of conflicts without requiring a full re-reconciliation of the object.

Currently, when a CRD update fails while reconciling an install plan due to a conflict, the install plan is permanantly marked as failed, which forces the user to delete the install plan and try again.

This PR treats conflicts as transient errors and performs retries with a default backoff.

Note that if a CRD update consistently results in conflict errors, it will still eventually be marked as failed, but this should happen extremely rarely (if ever) in practice.

Reviewer Checklist

• Implementation matches the proposed design, or proposal is updated to match implementation
• Sufficient unit test coverage
• Sufficient end-to-end test coverage
• Docs updated or added to /doc
• Commit messages sensible and descriptive

[timflannagan]

/lgtm

[njhale]

/approve

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: joelanford, njhale

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[joelanford]

/cherry-pick release-4.7

[openshift-cherrypick-robot]

@joelanford: #2293 failed to apply on top of branch "release-4.7":

Applying: installplans: retry crd updates on conflicts
Using index info to reconstruct a base tree...
M	pkg/controller/operators/catalog/step.go
Falling back to patching base and 3-way merge...
Auto-merging pkg/controller/operators/catalog/step.go
CONFLICT (content): Merge conflict in pkg/controller/operators/catalog/step.go
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
Patch failed at 0001 installplans: retry crd updates on conflicts
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".

In response to this:

/cherry-pick release-4.7

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