Bump external/Catch2 from `6783411` to `1f881ab` (#2237)

Bumps [external/Catch2](https://github.com/catchorg/Catch2) from `6783411` to `1f881ab`.
- [Release notes](https://github.com/catchorg/Catch2/releases)
- [Commits](6783411349...1f881ab464)

---
updated-dependencies:
- dependency-name: external/Catch2
  dependency-type: direct:production
...

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external/Catch2

@@ -1 +1 @@
-Subproject commit 6783411349db5a87718c9b7ba8b02e90e39d783e
+Subproject commit 1f881ab4641b866304b818a063164dae976dba5f