fix: command-line scheme switch values' spillover

[ckerr]

Description of Change

Fixes #19911: don't spill command-line switch scheme values into other switches.

In addition, this PR uses move semantics to move the tokens from a temporary container into their destination container.

Verified by adding this temporary code to the end of AtomContentClient::AddAdditionalSchemes():

#define DUMP_SCHEMES(name) \
  std::cout << #name << std::endl; \
  for (const auto& scheme : schemes->name) std::cout << scheme << ", "; \
  std::cout <<std::endl;

  DUMP_SCHEMES(service_worker_schemes)
  DUMP_SCHEMES(standard_schemes)
  DUMP_SCHEMES(secure_schemes)
  DUMP_SCHEMES(csp_bypassing_schemes)
  DUMP_SCHEMES(cors_enabled_schemes)

and invoking Electron with --standard-schemes=foo,bar,mum.

Without PR:

service_worker_schemes
file, 
standard_schemes
foo, bar, mum, chrome-extension, 
secure_schemes
foo, bar, mum, 
csp_bypassing_schemes
foo, bar, mum, 
cors_enabled_schemes
foo, bar, mum, 

With PR:

service_worker_schemes
file, 
standard_schemes
foo, bar, mum, chrome-extension, 
secure_schemes

csp_bypassing_schemes

cors_enabled_schemes

(file and chrome-extension are added automatically and unrelated to this PR).

ChecklistAtomContentClient::AddAdditionalSchemes

• PR description included and stakeholders cc'd
• npm test passes
• tests are changed or added
• PR title follows semantic commit guidelines
• PR release notes describe the change in a way relevant to app developers, and are capitalized, punctuated, and past tense.

Release Notes

Notes: Fixed command-line scheme arguments from spilling over into each other.

[deepak1556]

Thanks! 👍

[codebytere]

rad catch 🌟

[release-clerk]

Release Notes Persisted

Fixed command-line scheme arguments from spilling over into each other.

[trop]

I have automatically backported this PR to "5-0-x", please check out #19939

[trop]

I have automatically backported this PR to "6-0-x", please check out #19940

[trop]

I have automatically backported this PR to "7-0-x", please check out #19941

[trop]

A maintainer has manually backported this PR to "4-2-x", please check out #19954