fix(smus): fix refresh interval for tracking pending space nodes

[kzr-at-amazon]

Problem

• On transitioning from "Stopped" to/from "Running", the space node calls trackPendingNode() which adds it to the PollingSet. The PollingSet starts polling every 5 milliseconds which calls describeSpace + describeApp

Solution

• Update the polling interval to 5sec

---

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[amazon-inspector-ohio]

⏳ I'm reviewing this pull request for security vulnerabilities and code quality issues. I'll provide an update when I'm done

[github-actions]

• This pull request modifies code in src/* but no tests were added/updated.
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• This pull request implements a feat or fix, so it must include a changelog entry (unless the fix is for an unreleased feature). Review the changelog guidelines.
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[amazon-inspector-ohio]

✅ I finished the code review, and didn't find any security or code quality issues.

[vpbhargav]

One request, please check if we have other places where we have this issue as well. Also make the time value a constant with unit in name "...._POLLING_INTERVAL_SECS"

Fine to merge this now to mitigate impact and we can do it in some future PR.

[kzr-at-amazon]

It is fixed.

[vpbhargav]

Failing tests/builds are not related to change and seem to be flaky tests.