ci: remove unused variable from `.circleci/env.sh` (#34384)

Since #32537, the `.circleci/get-commit-range.js` script is no longer
used in `.circleci/env.sh`. This commit removes the now unused local
variable to the script's path.

PR Close #34384

.circleci/env.sh

@@ -3,7 +3,6 @@
 # Variables
 readonly projectDir=$(realpath "$(dirname ${BASH_SOURCE[0]})/..")
 readonly envHelpersPath="$projectDir/.circleci/env-helpers.inc.sh";
-readonly getCommitRangePath="$projectDir/.circleci/get-commit-range.js";
 
 # Load helpers and make them available everywhere (through `$BASH_ENV`).
 source $envHelpersPath;