OADP fails with "certificate signed by unknown authority"

Issue

• When configuring a DataProtectionApplication with a custom self-signed certificate, the Velero Pods still fail with the following error message:

  time="2022-05-30T12:56:43.424301918Z" level=error msg="response completed with error" err.code=unknown err.detail="s3aws: RequestError: send request failed\ncaused by: Get https://s3.example.com/my-velero-backup?delimiter=%2F&list-type=2&max-keys=1000&prefix=docker%2Fregistry%2Fv2%2Frepositories%2F: x509: certificate signed by unknown authority" err.message="unknown error" go.version=go1.13.4 http.request.host="192.168.10.10:5000" http.request.id=003909fa-f301-4e95-bd66-62261ae0bd18 http.request.method=GET http.request.remoteaddr="10.125.10.111:48738" http.request.uri="/v2/_catalog?n=5" http.request.useragent=kube-probe/1.21 http.response.contenttype=application/json http.response.duration=341.873257ms http.response.status=500 http.response.written=104