[main] (deps): Bump src/submodules/spa-templates (dotnet#48329)

Bumps [src/submodules/spa-templates](https://github.com/dotnet/spa-templates) from `2bc2374` to `3881d5a`.
- [Commits](dotnet/spa-templates@2bc2374...3881d5a)

---
updated-dependencies:
- dependency-name: src/submodules/spa-templates
  dependency-type: direct:production
...

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