fix:[SNOW-3444080] Preserve customer's original key order inside profiles.yml and env.yml; Refactor some code

[sfc-gh-yuding]

Pre-review checklist

• If my changes add or modify user-facing interface (commands, flags, output formats), I consulted maintainers and got sign-off beforehand (how).
  No user-facing interface change
• I've confirmed that instructions included in README.md are still correct after my changes in the codebase.
• I've added or updated unit tests to verify correctness of my new code.
• I've added or updated integration tests to verify correctness of my new code.
• Manually tested on macOS
• Manually tested on Windows
• I've confirmed my changes are up-to-date with the target branch.
• I've described my changes in RELEASE-NOTES.md (see when and how).
  Updated RELEASE-NOTES.md for profiles.yml changes. As for env.yaml, it's a prpr change, will include it in the RELEASE-NOTES.md when it becomes GA
• I've updated documentation if behavior changed.
  No behavior change

Changes description

• Extract repeated singular/plural logic into _plural(count, word) to avoid repeating the ternary three times (per PR fix: [SNOW-3444081] skip role validation in profiles.yml for Jinja-templated values and improve output message #3125 review)
• Pass sort_keys=False to yaml.safe_dump in _prepare_profiles_file and _write_env_file so staged files(profiles.yml and env.yml) both preserve the customer's original key order instead of sorting alphabetically

Verified on QA6 (DEXQA6) using the fix/dbt-yaml-staging-fixes branch.

Test files

profiles.yml — keys in a deliberately non-alphabetical order
(type → threads → account → user → password → role → warehouse → database → schema).
Alphabetical order would be account < database < password < role < schema < threads < type < user < warehouse.

env.yml — DBT_* keys in reverse-alphabetical order (ZETA → GAMMA → ALPHA → BETA).
Alphabetical order would be ALPHA < BETA < GAMMA < ZETA.

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Deploy

snow dbt deploy yuding_order_preservation_test --source ./dbt_order_test --force

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Verify staged file contents

snow sql -q "GET snow://dbt/YUDING_TEST.PUBLIC.YUDING_ORDER_PRESERVATION_TEST/versions/version\$1/profiles.yml file://$HOME/staged/"
snow sql -q "GET snow://dbt/YUDING_TEST.PUBLIC.YUDING_ORDER_PRESERVATION_TEST/versions/version\$1/env.yml    file://$HOME/staged/"

Staged profiles.yml

Key order matches the input (type before account, threads before database). ✅

Staged env.yml

Key order matches the input (ZETA → GAMMA → ALPHA → BETA, not sorted). ✅