Auto merge of #18059 - sendilkumarn:mito, r=nox

Using OnceCell<T> from Mitochondria

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- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #13402  (github issue number if applicable).

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components/script/Cargo.toml

@@ -56,6 +56,7 @@ lazy_static = "0.2"
 libc = "0.2"
 log = "0.3.5"
 metrics = {path = "../metrics"}
+mitochondria = "1.1.2"
 mime = "0.2.1"
 mime_guess = "1.8.0"
 msg = {path = "../msg"}