[8.11] fix(NA): missing --openssl-legacy-provider on webpack worker inside plugin helpers (#169030) (#169038)

# Backport

This will backport the following commits from `main` to `8.11`:
- [fix(NA): missing --openssl-legacy-provider on webpack worker inside
plugin helpers (#169030)](https://github.com/elastic/kibana/pull/169030)

<!--- Backport version: 8.9.7 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sqren/backport)

<!--BACKPORT [{"author":{"name":"Tiago
Costa","email":"tiago.costa@elastic.co"},"sourceCommit":{"committedDate":"2023-10-16T22:09:52Z","message":"fix(NA):
missing --openssl-legacy-provider on webpack worker inside plugin
helpers (#169030)\n\nThis PR fixes a problem inside plugin-helpers as
the webpack runner was\r\nrunning without `--openssl-legacy-provider`
which breaks in the latest\r\nnode
version.","sha":"c3936571fcbd161b479b7b1908793fe8ccc5ebdf","branchLabelMapping":{"^v8.12.0$":"main","^v(\\d+).(\\d+).\\d+$":"$1.$2"}},"sourcePullRequest":{"labels":["chore","Team:Operations","release_note:skip","backport:prev-minor","v8.12.0"],"number":169030,"url":"https://github.com/elastic/kibana/pull/169030","mergeCommit":{"message":"fix(NA):
missing --openssl-legacy-provider on webpack worker inside plugin
helpers (#169030)\n\nThis PR fixes a problem inside plugin-helpers as
the webpack runner was\r\nrunning without `--openssl-legacy-provider`
which breaks in the latest\r\nnode
version.","sha":"c3936571fcbd161b479b7b1908793fe8ccc5ebdf"}},"sourceBranch":"main","suggestedTargetBranches":[],"targetPullRequestStates":[{"branch":"main","label":"v8.12.0","labelRegex":"^v8.12.0$","isSourceBranch":true,"state":"MERGED","url":"https://github.com/elastic/kibana/pull/169030","number":169030,"mergeCommit":{"message":"fix(NA):
missing --openssl-legacy-provider on webpack worker inside plugin
helpers (#169030)\n\nThis PR fixes a problem inside plugin-helpers as
the webpack runner was\r\nrunning without `--openssl-legacy-provider`
which breaks in the latest\r\nnode
version.","sha":"c3936571fcbd161b479b7b1908793fe8ccc5ebdf"}}]}]
BACKPORT-->

Co-authored-by: Tiago Costa <tiago.costa@elastic.co>

packages/kbn-plugin-helpers/src/tasks/optimize.ts

@@ -63,7 +63,7 @@ export async function optimize({
 
     const proc = fork(require.resolve('./optimize_worker'), {
       cwd: REPO_ROOT,
-      execArgv: ['--require=@kbn/babel-register/install'],
+      execArgv: ['--require=@kbn/babel-register/install', '--openssl-legacy-provider'],
       stdio: ['ignore', 'pipe', 'pipe', 'ipc'],
     });