Release: Bump version to 12.4.0-pre (#113480)

bump version 12.4.0-pre

Co-authored-by: grafana-delivery-bot[bot] <grafana-delivery-bot[bot]@users.noreply.github.com>

e2e-playwright/test-plugins/grafana-extensionstest-app/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@test-plugins/extensions-test-app",
-  "version": "12.3.0-pre",
+  "version": "12.4.0-pre",
   "private": true,
   "scripts": {
     "build": "NODE_OPTIONS='--experimental-strip-types --no-warnings=ExperimentalWarning' webpack -c ./webpack.config.ts --env production",

e2e-playwright/test-plugins/grafana-test-datasource/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@test-plugins/grafana-e2etest-datasource",
-  "version": "12.3.0-pre",
+  "version": "12.4.0-pre",
   "private": true,
   "scripts": {
     "build": "NODE_OPTIONS='--experimental-strip-types --no-warnings=ExperimentalWarning' webpack -c ./webpack.config.ts --env production",