Fix toolchain-desktop-macos CI jobs [ci full]

When NSS was updated in mozilla#5752, the SHA256 value in build-nss-desktop.sh was not
updated. This fixes that hash value and updates the docs.

docs/howtos/upgrading-nss-guide.md

@@ -32,9 +32,10 @@ We use a Linux TC worker for cross-compiling NSS for iOS, Android and Linux desk
     > usually a description with something like _`Added tag NSS_3_90_RTM`_
 2. Select the build for the following system(s) (first task with the title "B"):
     * For Intel MacOS: `mac opt-static`
-3. Update [taskcluster/ci/fetch/kind.yml](https://github.com/mozilla/application-services/blob/main/taskcluster/ci/fetch/kind.yml), specifically `nss-artifact` task to the appropiate `url` and `checksum` and `size`
+3. Update [taskcluster/ci/fetch/kind.yml](https://github.com/mozilla/application-services/blob/main/taskcluster/ci/fetch/kind.yml), specifically `nss-artifact` task to the appropriate `url` and `checksum` and `size`
     > Note: _To get the checksum, you can run `shasum -a 256 {path-to-artifact}` or you can make a PR and see the output of the failed log._
-4. Open a pull request with these changes and it should update the [Taskcluster artifact](https://firefox-ci-tc.services.mozilla.com/tasks/index/app-services.cache.level-1.content.v1.nss-artifact/latest)
+4. Update the SHA256 value for darwin cross-compile in [libs/build-nss-desktop.sh](https://github.com/mozilla/application-services/blob/main/libs/build-nss-desktop.sh) to the same checksum as above.
+5. Open a pull request with these changes and it should update the [Taskcluster artifact](https://firefox-ci-tc.services.mozilla.com/tasks/index/app-services.cache.level-1.content.v1.nss-artifact/latest)
 
 ---
 

libs/build-nss-desktop.sh

@@ -59,7 +59,7 @@ fi
 if [[ "${CROSS_COMPILE_TARGET}" =~ "darwin" ]]; then
   #From https://firefox-ci-tc.services.mozilla.com/tasks/index/app-services.cache.level-3.content.v1.nss-artifact/latest
   curl -sfSL --retry 5 --retry-delay 10 -O "https://firefox-ci-tc.services.mozilla.com/api/index/v1/task/app-services.cache.level-3.content.v1.nss-artifact.latest/artifacts/public/dist.tar.bz2"
-  SHA256="1f667d17cd1f9c869de413c3f9797378af5b49314738d2364ca178b651eacd29"
+  SHA256="9573e640797200891dadc6401cdd9cb06e3fd48518a146cf2f578e83127cb7f2"
   echo "${SHA256}  dist.tar.bz2" | shasum -a 256 -c - || exit 2
   tar xvjf dist.tar.bz2 && rm -rf dist.tar.bz2
   NSS_DIST_DIR=$(abspath "dist")