chore: update evergreen to filter with install

[gagik]

Stacked on #2613

This should noticably reduce test execution time for some of the smaller packages.

Some examples (around ~30s reduction! compared to base):

test_cli_repl
Duration: 13m 31s
Base commit duration: 14m 56s

test_errors
Duration: 1m 3s
Base commit duration: 1m 35s

test_shell_api
Duration: 5m 12s
Base commit duration: 5m 27s

[Copilot]

Pull request overview

This PR optimizes Evergreen CI builds by enabling selective workspace installation through a new MONGOSH_INSTALL_WORKSPACE environment variable. When set, only the specified workspace and its dependencies are installed, reducing installation time for smaller packages.

Key changes:

• Added conditional workspace-specific installation logic to the npm dependency installation script
• Introduced MONGOSH_INSTALL_WORKSPACE environment variable in Evergreen configuration
• Applied workspace-specific installation settings to all 26 package test tasks

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
.evergreen/install-npm-deps.sh	Added conditional logic to install only specified workspace when MONGOSH_INSTALL_WORKSPACE is set, including special handling for mongodb-client-encryption optional dependency
.evergreen/evergreen.yml.in	Added MONGOSH_INSTALL_WORKSPACE variable to environment and templated task configuration to pass workspace-specific values
.evergreen.yml	Applied mongosh_install_workspace setting to all 26 package-specific test tasks with appropriate package names

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