fix(helm): dont specify a default type for extraSecrets

[wheelerlaw]

Generally it is better to use objects/dicts over lists because the former can be used in the exact same way as the latter and the former adds the functionality of being able to specify which element by name.

Also, in Helm, lists are overridden completely when using subsequent values.yaml files. On the other hand, objects/dicts are merged, making it easier to create a base values.yaml and override it with values-{env}.yaml without having to copy/paste a lot of stuff.

See this StackOverflow question: https://stackoverflow.com/questions/59394422/helm-charts-with-multiple-lists-in-multiple-values-files

Checklist prior to review

• Link to docs PR or issue --
• Link to UI issue or PR --
• Is the issue worked on linked? --
• The PR does not hardcode values that might break projects that depend on kuma (e.g. "kumahq" as a image registry) --
• The PR will work for both Linux and Windows, system specific functions like syscall.Mkfifo have equivalent implementation on the other OS --
• Unit Tests --
• E2E Tests --
• Manual Universal Tests --
• Manual Kubernetes Tests --
• Do you need to update UPGRADE.md? --
• Does it need to be backported according to the backporting policy? --
• Do you need to explicitly set a > Changelog: entry here or add a ci/ label to run fewer/more tests?

[michaelbeaumont]

Nice!