[Ubuntu] Get toolset value function. (#2435)

* [macOS] Fail Pester tests on error

* return it back

* [Ubuntu] add get_toolset_values function

* added fix

* fix all nitpicks

* try to get rid brackets

* removed brackets.

* pipx-package fix

images/linux/scripts/installers/dotnetcore-sdk.sh

@@ -9,9 +9,8 @@ source $HELPER_SCRIPTS/install.sh
 source $HELPER_SCRIPTS/os.sh
 
 # Ubuntu 20 doesn't support EOL versions
-toolset="$INSTALLER_SCRIPT_FOLDER/toolset.json"
-LATEST_DOTNET_PACKAGES=$(jq -r '.dotnet.aptPackages[]' $toolset)
-versions=$(jq -r '.dotnet.versions[]' $toolset)
+LATEST_DOTNET_PACKAGES=$(get_toolset_value '.dotnet.aptPackages[]')
+DOTNET_VERSIONS=$(get_toolset_value '.dotnet.versions[]')
 
 mksamples()
 {
@@ -43,7 +42,7 @@ done
 
 # Get list of all released SDKs from channels which are not end-of-life or preview
 sdks=()
-for version in ${versions[@]}; do
+for version in ${DOTNET_VERSIONS[@]}; do
     release_url="https://dotnetcli.blob.core.windows.net/dotnet/release-metadata/${version}/releases.json"
     download_with_retries "${release_url}" "." "${version}.json"
     releases=$(cat "./${version}.json")