Remove `${CI_SERVER_PORT}` in NPM `.gitlab-ci.yml` template

What does this MR do?

This MR replaces //${CI_SERVER_HOST}:${CI_SERVER_PORT}/api/... with //${CI_SERVER_HOST}/api/... in the _authToken setting sections in order to make npm CI jobs login to GitLab npm registry successfully.

No server ports are required for the authentication format, according to https://docs.npmjs.com/using-private-packages-in-a-ci-cd-workflow.

Screenshots (strongly suggested)

When I use the original npm template with GitLab's NodeJS Express project template (before):

npm notice === Tarball Details === 
npm notice name:          @foo/bar             
npm notice version:       0.0.0                                   
npm notice filename:      @foo/bar-0.0.0.tgz   
npm notice package size:  3.7 kB                                  
npm notice unpacked size: 8.1 kB                                  
npm notice shasum:        afb7ece07e4fcc5b151c144af6f960c6dc0c8616
npm notice integrity:     sha512-pr3IVOvDZqwh2[...]gKoV/g0u9qACA==
npm notice total files:   15                                      
npm notice 
npm ERR! code ENEEDAUTH
npm ERR! need auth This command requires you to be logged in.
npm ERR! need auth You need to authorize this machine using `npm adduser`
npm ERR! A complete log of this run can be found in:
npm ERR!     /root/.npm/_logs/2021-05-27T09_08_14_099Z-debug.log
No new version of @foo/bar published. This is most likely because version 0.0.0 already exists in GitLab's NPM registry.

When I remove :${CI_SERVER_PORT}s in the npm template (after):

npm notice === Tarball Details === 
npm notice name:          @foo/bar             
npm notice version:       0.0.0                                   
npm notice filename:      @foo/bar-0.0.0.tgz   
npm notice package size:  3.7 kB                                  
npm notice unpacked size: 8.1 kB                                  
npm notice shasum:        4ca3c092da8e3c515c7bdf6ff5b4806b3c129a76
npm notice integrity:     sha512-LB4ZlaiU9dBgn[...]uOmdyZhYvlY/g==
npm notice total files:   15                                      
npm notice 
+ @foo/bar@0.0.0
Successfully published version 0.0.0 of @foo/bar to GitLab's NPM registry: https://gitlab.com/foo/bar/-/packages

Does this MR meet the acceptance criteria?

Conformity

• I have included a changelog entry, or it's not needed. (Does this MR need a changelog?)
• I have added/updated documentation, or it's not needed. (Is documentation required?)
• I have properly separated EE content from FOSS, or this MR is FOSS only. (Where should EE code go?)
• I have added information for database reviewers in the MR description, or it's not needed. (Does this MR have database related changes?)
• I have self-reviewed this MR per code review guidelines.
• This MR does not harm performance, or I have asked a reviewer to help assess the performance impact. (Merge request performance guidelines)
• I have followed the style guides.

Availability and Testing

• I have added/updated tests following the Testing Guide, or it's not needed. (Consider all test levels. See the Test Planning Process.)
• I have tested this MR in all supported browsers, or it's not needed.
• I have informed the Infrastructure department of a default or new setting change per definition of done, or it's not needed.

Security

Does this MR contain changes to processing or storing of credentials or tokens, authorization and authentication methods or other items described in the security review guidelines? If not, then delete this Security section.

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team