Maestro (PCS) has issues checking PullRequest status

[dkurepa]

Starting on December 20th, we've been getting a ton of exceptions 403 (Forbidden) when trying to get GitHub PR statuses. However, this doesn't happen for all repos, the traces clearly show it works in some cases.
Our logging currently doesn't tell us a lot, so the best course of action might be to improve it first, and then figure out why some PR statuses can't be read, once we know which those are

[dkurepa]

based on https://ms.portal.azure.com#@72f988bf-86f1-41af-91ab-2d7cd011db47/blade/Microsoft_OperationsManagementSuite_Workspace/Logs.ReactView/resourceId/%2Fsubscriptions%2Ffbd6122a-9ad3-42e4-976e-bccb82486856%2FresourceGroups%2Fproduct-construction-service%2Fproviders%2Fmicrosoft.insights%2Fcomponents%2Fproduct-construction-service-ai-prod/source/LogsBlade.AnalyticsShareLinkToQuery/q/H4sIAAAAAAAAA61Sy07DMBC89ytWudBKCWmTlhakHqBUFCEVhJA4IsfZJIbEDvaaAuLj2YiHeNwKPlm7szM7oyUrJLreC2wqtAiyNj6%252FuTQ1nmpHQkuE%252BRyC1prcS4qk4arlnzI66opRlAyT8ShJh0k0itJ0f4J7kyIR0XRvPMv28%252Bn9w6zYBJ%252F8DTonSoRKOAjWuAEyd6jBZCSUxhwKY%252BFE0cpnoLoF6lp0WpAm4%252BlsFAC3v1EshKx4bHsW7lpyG0UVkxlf53qHoETqGuQdmAIuLqEiat1BHItW7ZaM9dmuNE1ssTUuzg1ppM4jPhLqHEprfAtzkMJhvwf8%252Fmg75KHldRD%252B5trKP9MtDher5fEPxv%252FLghWODo%252Fh6vxsuX4XCQzxBQQDjsn5phFWPfO5Ga%252BpP4DsCTKl%252B6R4FRJNG0LaDMK3IHmAL%252B0WJb3Bb0L4gvuAWA4eLSNq32hZsZFXhyZONNoCAAA%253D/timespan/PT4H, the issue seems to be that the token expires, and we don't regenerate a new one until the one in the cache times out.