fix: repair partial build after npm upgrade

[dhhyi]

PR Type

[x] Bugfix
[x] Build-related changes

What Is the Current Behavior?

After npm upgrade, the command npm config set active-themes does no longer work for a partial build in the Dockerfile.
Test by uncommenting the build args of the SSR image activeThemes: b2c in the docker-compose.yml:

intershop-pwa/docker-compose.yml

Lines 6 to 12 in 2c79d97

	pwa:
	build:
	context: .
	args:
	serviceWorker: 'false'
	# activeThemes: b2b
	# activeThemes: b2c

What Is the New Behavior?

Using npm pkg set config.active-themes to modify the package.json in the Dockerfile when building.

Does this PR Introduce a Breaking Change?

[ ] Yes
[x] No

Other Information

AB#88442