BB2-3256: Updated queryset for auth grants

JIRA Ticket: BB2-3256

User Story or Bug Summary:

Include Only apps with active DAG in /v1/o/tokens endpoint response (for medicare.gov "connected apps" page)

Updates queryset for auth grants returned by the /tokens endpoint for the medicare.org Connected Apps view.

If you're reviewing this PR, please check these things, in particular:

Finding a way to test this manually would be great! As is, the unit test in apps.dot_ext.tests.test_views.TestTokenView is the only good test.

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If the answer to any of the questions below is Yes, then here's a link to the associated Security Impact Assessment (SIA), security checklist, or other similar document in Confluence: N/A.
- Does this PR add any new software dependencies? No.
- Does this PR modify or invalidate any of our security controls? No.
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If the answer to any of the questions below is Yes, then please add a Security Engineer and ISSO as a reviewer, and note that this PR should not be merged unless/until he also approves it.
- Do you think this PR requires additional review of its security implications for other reasons? No.

[ ] Yes, there are migrations
- [ ] The migrations should be run PRIOR to the code being deployed
- [ ] The migrations should be run AFTER the code is deployed
- [ ] There is a more complicated migration plan (downtime, etc)
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I have gone through and verified that...:

[x] This PR is reasonably limited in scope, to help ensure that:
1. It doesn't unnecessarily tie a bunch of disparate features, fixes, refactorings, etc. together.
2. There isn't too much of a burden on reviewers.
3. Any problems it causes have a small "blast radius".
4. It'll be easier to rollback if that becomes necessary.
[x] I have named this PR and its branch such that they'll be automatically be linked to the (most) relevant Jira issue, per: https://confluence.atlassian.com/adminjiracloud/integrating-with-development-tools-776636216.html.
[x] This PR includes any required documentation changes, including README updates and changelog / release notes entries.
[x] All new and modified code is appropriately commented, such that the what and why of its design would be reasonably clear to engineers, preferably ones unfamiliar with the project.
[x] All tech debt and/or shortcomings introduced by this PR are detailed in TODO and/or FIXME comments, which include a JIRA ticket ID for any items that require urgent attention.
[x] Reviews are requested from both:
- At least two other engineers on this project, at least one of whom is a senior engineer or owns the relevant component(s) here.
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[x] Any deviations from the other policies in the DASG Engineering Standards are specifically called out in this PR, above.
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CMSgov / bluebutton-web-server