diagnostics: Integrate system data expectation-not-met error metrics

Bug: b/243808946
Test: ash_webui_unittest --gtest_filter=SystemDataProviderTest*

Change-Id: I536b797feb50158d5e9be5fe5dc11f12388e5247
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3856811


Reviewed-by: Ashley Prasad <ashleydp@google.com>
Commit-Queue: Wenyu Zhang <zhangwenyu@google.com>
Cr-Commit-Position: refs/heads/main@{#1041594}