compute,storage: downgrade config update logs

[teskje]

This PR downgrades the "Applying configuration update" logs from info to debug. They have become extremely noisy over time as we have accumulated more config options, and especially with the introduction of the dyncfgs.

Motivation

• This PR fixes a recognized bug.

Fixes https://github.com/MaterializeInc/database-issues/issues/9660

Tips for reviewer

I would prefer to either (a) log only actual config changes or (b) send only actual config changes from envd to clusterd. But I didn't find a good way to implement (a) with our current {Compute,Storage}Parameters definition and (b) requires a refactor of adapter code I'm not very familiar with.

Checklist

• [ ] This PR has adequate test coverage / QA involvement has been duly considered. (trigger-ci for additional test/nightly runs)
• [ ] This PR has an associated up-to-date design doc, is a design doc (template), or is sufficiently small to not require a design.
• [ ] If this PR evolves an existing $T ⇔ Proto$T mapping (possibly in a backwards-incompatible way), then it is tagged with a T-proto label.
• [ ] If this PR will require changes to cloud orchestration or tests, there is a companion cloud PR to account for those changes that is tagged with the release-blocker label (example).
• [ ] If this PR includes major user-facing behavior changes, I have pinged the relevant PM to schedule a changelog post.

[petrosagg]

but just last week this was crucial to me to debug an issue

But how often have you had such a debugging task? And, was the problem related to the mechanism of propagating configuration to clusters or you just wanted to see what was the value of a particular config at a particular time? The latter need can be served by our configuration service (LD) which tracks the history of each variable.

In general, I think we need a higher bar for having things be logged at info level, leaning towards things that are:

1. High value
2. Low traffic
3. Can't be deduced after the fact

I don't think the LD configs meet that bar so I'm strongly in favor of merging this PR