fix unit for metric unload for calculated db load

[denis-yuen]

Description Adds a unit for calculated database load (and other future ratio gauges)

Review Instructions If you chart the metric after deployment in qa, it may show up as a percentage (upper left) https://stackoverflow.com/questions/46711700/can-i-change-metric-units-on-cloudwatch

Issue Follow-up for https://github.com/dockstore/dockstore/pull/5873

Security and Privacy

None

Please make sure that you've checked the following before submitting your pull request. Thanks!

• [x] Check that you pass the basic style checks and unit tests by running mvn clean install
• [x] Ensure that the PR targets the correct branch. Check the milestone or fix version of the ticket.
• [x] Follow the existing JPA patterns for queries, using named parameters, to avoid SQL injection
• [x] If you are changing dependencies, check the Snyk status check or the dashboard to ensure you are not introducing new high/critical vulnerabilities
• [x] Assume that inputs to the API can be malicious, and sanitize and/or check for Denial of Service type values, e.g., massive sizes
• [x] Do not serve user-uploaded binary images through the Dockstore API
• [x] Ensure that endpoints that only allow privileged access enforce that with the @RolesAllowed annotation
• [x] Do not create cookies, although this may change in the future
• [x] If this PR is for a user-facing feature, create and link a documentation ticket for this feature (usually in the same milestone as the linked issue). Style points if you create a documentation PR directly and link that instead.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 66.66667% with 2 lines in your changes are missing coverage. Please review.

Project coverage is 70.57%. Comparing base (c0091ab) to head (d239475).

Files	Patch %	Lines
...ore/webservice/DockstoreWebserviceApplication.java	33.33%	2 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #5876 +/- ## ============================================= + Coverage 64.15% 70.57% +6.42% - Complexity 4627 5035 +408 ============================================= Files 371 371 Lines 19189 19190 +1 Branches 2005 2006 +1 ============================================= + Hits 12311 13544 +1233 + Misses 5906 4649 -1257 - Partials 972 997 +25 ``` | [Flag](https://app.codecov.io/gh/dockstore/dockstore/pull/5876/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dockstore) | Coverage Δ | | |---|---|---| | [integrationtests](https://app.codecov.io/gh/dockstore/dockstore/pull/5876/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dockstore) | `58.47% <66.66%> (+4.30%)` | :arrow_up: | | [languageparsingtests](https://app.codecov.io/gh/dockstore/dockstore/pull/5876/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dockstore) | `11.07% <16.66%> (-0.01%)` | :arrow_down: | | [localstacktests](https://app.codecov.io/gh/dockstore/dockstore/pull/5876/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dockstore) | `21.69% <66.66%> (-0.01%)` | :arrow_down: | | [toolintegrationtests](https://app.codecov.io/gh/dockstore/dockstore/pull/5876/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dockstore) | `17.39% <16.66%> (-0.01%)` | :arrow_down: | | [unit-tests_and_non-confidential-tests](https://app.codecov.io/gh/dockstore/dockstore/pull/5876/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dockstore) | `28.47% <66.66%> (+2.38%)` | :arrow_up: | | [workflowintegrationtests](https://app.codecov.io/gh/dockstore/dockstore/pull/5876/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dockstore) | `38.65% <66.66%> (+7.78%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dockstore#carryforward-flags-in-the-pull-request-comment) to find out more.

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[sonarcloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
85.7% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud