[CI] Fix inverted DRY_RUN behaviour (#184841)

## Summary
We added this check in #177736 but
we haven't really tested it in action, it looks like we had the dry-run
behaviour inverted.

.buildkite/scripts/serverless/emergency_release/trigger_container_build.ts

@@ -16,16 +16,16 @@ async function main() {
   const commitSha = process.env.OVERRIDE_COMMIT || process.env.BUILDKITE_COMMIT;
 
   if (!isCurrentHeadInMain(commitSha!)) {
-    if (!DRY_RUN) {
+    if (DRY_RUN) {
       console.log(
         `DRY_RUN: Commit ${commitSha} isn't in main, triggering container build :green_heart:`
       );
     } else {
       console.log(`Commit ${commitSha} isn't in main, triggering container build :green_heart:`);
-      uploadTriggerBuildStep();
+      uploadTriggerBuildStep(commitSha!);
     }
   } else {
-    if (!DRY_RUN) {
+    if (DRY_RUN) {
       console.log(`DRY_RUN: Commit ${commitSha} is in main, no build necessary :yellow_heart:`);
     } else {
       console.log(`Commit ${commitSha} is in main, no trigger necessary :yellow_heart:`);
@@ -41,12 +41,14 @@ function isCurrentHeadInMain(commitSha: string) {
   return parseInt(containmentTest, 10) >= 1;
 }
 
-function uploadTriggerBuildStep() {
+function uploadTriggerBuildStep(commitSha: string) {
   const triggerStep: BuildkiteTriggerStep = {
     label: ':point_right: Trigger emergency commit container build',
     trigger: 'kibana-artifacts-container-image',
     build: {
       message: `Triggered by '${process.env.BUILDKITE_PIPELINE_NAME || 'unknown'}'`,
+      branch: process.env?.BUILDKITE_BRANCH || 'main',
+      commit: commitSha,
       env: {},
     },
   };