ci(NODE-7496): pin npm to 11.11.1 for Node 22 build variants

[tadjik1]

Description

Summary of Changes

Override NPM_VERSION for all tasks using Node.js v22 to avoid failures on npm install -g npm@latest.

Notes for Reviewers

This problem can easily be reproduced locally by installing Node.js v22 and then try to upgrate npm to latest using bundled version (this is what evergreen tools do):

➜  dbx nvm install 22
v22.22.2 is already installed.
Now using node v22.22.2 (npm v10.9.7)
➜  dbx npm install -g npm@latest
npm error code MODULE_NOT_FOUND
npm error Cannot find module 'promise-retry'
npm error Require stack:
...

This only reproduced on Node.js v22 (and bundled npm version 10.9.7). Node.js v20.19.0, as well as 24 - upgrades npm as expected.

What is the motivation for this change?

Release Highlight

Release notes highlight

Double check the following

• Lint is passing (npm run check:lint)
• Self-review completed using the steps outlined here
• PR title follows the correct format: type(NODE-xxxx)[!]: description
  • Example: feat(NODE-1234)!: rewriting everything in coffeescript
• Changes are covered by tests
• New TODOs have a related JIRA ticket

[Copilot]

Pull request overview

Pins npm for Node.js v22 Evergreen executions to avoid failures when upgrading npm from the bundled Node 22 npm (v10.9.7) during dependency installation.

Changes:

• Add NPM_VERSION=11.11.1 expansion to generated Node 22 buildvariants.
• Override install dependencies for the Node 22 unit-test task to pass NPM_VERSION=11.11.1.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
.evergreen/generate_evergreen_tasks.js	Adds logic to pin npm for Node 22 buildvariants and the Node 22 unit-test task.
.evergreen/config.yml	Updates the generated Evergreen config to include the npm pin in Node 22 task/variant definitions.

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[PavelSafronov]

Let's also add a TODO JIRA item for unpinning this.