ci: reduce jobs to 4

[pixincreate]

Type of Change

• [ ] Bugfix
• [ ] New feature
• [ ] Enhancement
• [x] Refactoring
• [ ] Dependency updates
• [ ] Documentation
• [x] CI/CD

Description

this pr reduces the jobs required by cargo to build the router for cypress tests from 6 to 4 as a measure to reduce memory consumption that lead to abrupt failures like this one: https://github.com/juspay/hyperswitch/actions/runs/11107215802?pr=6159 (memory usage hit 15.9 gb at one point)

Additional Changes

• [ ] This PR modifies the API contract
• [ ] This PR modifies the database schema
• [ ] This PR modifies application configuration/environment variables

Motivation and Context

reduce failures in ci

How did you test it?

it should not fail in ci abruptly.

Checklist

• [ ] I formatted the code cargo +nightly fmt --all
• [ ] I addressed lints thrown by cargo clippy
• [x] I reviewed the submitted code
• [ ] I added unit tests for my changes where possible

[semanticdiff-com[bot]]

Review changes with SemanticDiff.