fix: added role for editedby and closedby user

[sundasnoreen12]

INF-818

Description

1. Role info needs to be present in edited and closed banner.
2. Username and role color in the banner should match figma.

Before	After

Merge Checklist

• [ ] If your update includes visual changes, have they been reviewed by a designer? Send them a link to the Sandbox, if applicable.
• [ ] Is there adequate test coverage for your changes?

Post-merge Checklist

• [ ] Deploy the changes to prod after verifying on stage or ask @openedx/edx-infinity to do it.
• [ ] 🎉 🙌 Celebrate! Thanks for your contribution.

[codecov[bot]]

Codecov Report

Patch coverage: 100.00% and project coverage change: +0.01 :tada:

Comparison is base (009417b) 92.15% compared to head (2c6a75e) 92.17%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #498 +/- ## ========================================== + Coverage 92.15% 92.17% +0.01% ========================================== Files 163 164 +1 Lines 3251 3259 +8 Branches 889 891 +2 ========================================== + Hits 2996 3004 +8 Misses 236 236 Partials 19 19 ``` | [Impacted Files](https://codecov.io/gh/openedx/frontend-app-discussions/pull/498?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=openedx) | Coverage Δ | | |---|---|---| | [src/discussions/common/AlertBanner.jsx](https://codecov.io/gh/openedx/frontend-app-discussions/pull/498?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=openedx#diff-c3JjL2Rpc2N1c3Npb25zL2NvbW1vbi9BbGVydEJhbm5lci5qc3g=) | `100.00% <100.00%> (ø)` | | | [src/discussions/common/AlertBar.jsx](https://codecov.io/gh/openedx/frontend-app-discussions/pull/498?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=openedx#diff-c3JjL2Rpc2N1c3Npb25zL2NvbW1vbi9BbGVydEJhci5qc3g=) | `100.00% <100.00%> (ø)` | | Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=openedx). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=openedx)

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