fix(deployment): Use a different key for sealed secrets data

[theosanderson]

I just spent a loooong time debugging a confusing issue on Pathoplexus. It manifested as the database sealed secret that couldn't be extracted as it appeared to be corrupt. It was very confusing because I could see the sealed secrets I had configured in values yaml and they hadn't changed. It turned out that what had happened was that we added a new key host to the database secret in the default values.yaml recently. That default values yaml doesn't use sealed secrets at all, it defines them in a raw format. But because that value hadn't been added to pathoplexus's values.yaml in any form, and because pathoplexus values.yaml redefines the database secret as a sealed secret, what ended up happening was that the sealed secrets controller attempted to extract the host key, merged in from the default values yaml, even though that had never been sealed. This was so confusing to debug that I want to avoid it ever happening again, so now we will store sealed secrets under encryptedData not data so that you cannot get merging of a sealed and unsealed secret.

https://different-key-sealed-secr.loculus.org/