fix(bundle): honor runtime no-downloads setting

[subotac]

Summary

• honor the runtime and saved no-download settings when resolving NSIS, WiX, and linuxdeploy
• continue using cached bundler tools when downloads are disabled
• add regression coverage for both missing and cached tools

Fixes #5703.

Testing

• cargo test -p dioxus-cli runtime_no_downloads_applies_to_bundler_tools -- --nocapture
• cargo test -p dioxus-cli -- --skip test_harnesses::run_harness
• cargo check -p dioxus-cli --tests