[csharp/Tests] Update mcr.microsoft.com/devcontainers/dotnet Docker t… #998

Job	Run time
Find all Bootstraps with a devcontainer spec	2s
Validate Bootstrap clojure	23s
Validate Bootstrap csharp	38s
Validate Bootstrap denojs	10s
Validate Bootstrap elixir	49s
Validate Bootstrap elm	31s
Validate Bootstrap fsharp	34s
Validate Bootstrap gleam	32s
Validate Bootstrap golang	43s
Validate Bootstrap haskell	1m 43s
Validate Bootstrap java	22s
Validate Bootstrap kotlin	45s
Validate Bootstrap nodejs	41s
Validate Bootstrap php	24s
Validate Bootstrap purescript	43s
Validate Bootstrap python	29s
Validate Bootstrap rescript	27s
Validate Bootstrap ruby	36s
Validate Bootstrap rust	31s
Validate Bootstrap scala2	44s
Validate Bootstrap scala3	49s
Validate Bootstrap typescript	26s
Validate Bootstrap zig	45s
	13m 47s

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