triage script is sometimes producing "<UNKNOWN>" for the titles of PR's

While doing triage this week for: https://perf.rust-lang.org/perf/triage?start=e2116acae59654bfab2a9729a024f3e2fd6d4b02

I found that the title for every PR is listed as "" in the report.

For example:

#### Regressions

<UNKNOWN> [#91224](https://github.com/rust-lang/rust/issues/91224)
- Moderate regression in [instruction counts](https://perf.rust-lang.org/compare.html?start=c5c94945096265b6d675b2f55a247c4799de8d87&end=0b6f079e4987ded15c13a15b734e7cfb8176839f&stat=instructions:u) (up to 0.8% on `incr-unchanged` builds of `externs`)


<UNKNOWN> [#91760](https://github.com/rust-lang/rust/issues/91760)
- Very large regression in [instruction counts](https://perf.rust-lang.org/compare.html?start=0b42deaccc2cbe17a68067aa5fdb76104369e1fd&end=f0448f44bcda55fd9eb71da82495ef648eedb4e4&stat=instructions:u) (up to 5.5% on `incr-unchanged` builds of `inflate`)


<UNKNOWN> [#91776](https://github.com/rust-lang/rust/issues/91776)
- Very large regression in [instruction counts](https://perf.rust-lang.org/compare.html?start=4a66a704b2c3d30ff07d89380ebb9ba3de3b3182&end=b9a37ad0d995c71518629b032f8e816e1efa8bca&stat=instructions:u) (up to 6.2% on `incr-unchanged` builds of `inflate`)

[...]

Start by reproducing the linked triage report and trace how PR titles are fetched and rendered by the triage script. Confirm why the affected entries become ""; done means the report displays the actual titles for those PRs.