Enhance reporting, add shellcheck (#28240)

* Enhance reporting, add shellcheck

---------

Co-authored-by: Mattermost Build <build@mattermost.com>

e2e-tests/.ci/report.collect.sh

@@ -0,0 +1,27 @@
+#!/bin/bash
+# SC2034: <variable> appears unused.
+# https://www.shellcheck.net/wiki/SC2034
+# shellcheck disable=SC2034
+# shellcheck disable=SC2086,SC2223
+
+set -e -u -o pipefail
+cd "$(dirname "$0")"
+. .e2erc
+
+# The collected data will be written to the "e2e-tests/cypress/results/" directory
+cd ../cypress/
+if [ ! -d "results/" ]; then
+  mme2e_log "Error: 'results/' directory does not exist. Aborting report data collection." >&2
+  exit 1
+fi
+
+# If the Automation Dashboard is used, try to collect run data from it
+if [ -n "${AUTOMATION_DASHBOARD_URL:-}" ]; then
+  mme2e_log "Automation Dashboard usage detected: retrieving cycle results"
+  # Assume that we're in the cypress dir and that the 'results/' directory exists
+  : ${BUILD_ID:?}
+  AD_CYCLE_FILE="results/ad_cycle.json"
+  AD_SPECS_FILE="results/ad_specs.json"
+  curl -o "$AD_CYCLE_FILE" -fsSL "${AUTOMATION_DASHBOARD_URL}/cycle?build=${BUILD_ID}"
+  curl -o "$AD_SPECS_FILE" -fsSL "${AUTOMATION_DASHBOARD_URL}/executions/specs?cycle_id=$(jq -r .id "$AD_CYCLE_FILE")"
+fi