fix(ci): use cargo build for dioxus example

[james-crabnebula]

Summary

• Replace dx build --platform desktop --release with cargo build --release in the dioxus example's before-packaging-command
• Remove the cargo binstall dioxus-cli step from build-examples.yml (no longer needed)

Why

The dioxus example is a plain desktop app (20 lines, no manganis assets or dx-specific features). dx build outputs to target/dx/dioxus-example/release/ instead of target/release/, causing cargo-packager to fail finding the binary. On Ubuntu 22.04, dx also requires GLIBC 2.38+ which isn't available.

Every other Rust example (wry, egui, slint) already uses cargo build --release.

Test plan

• Local build: cargo build --release -p dioxus-example produces binary at target/release/dioxus-example
• Full packaging pipeline: all 7 examples package successfully (21 packages, 14 signatures)
• macOS: unit tests, E2E updater, audit, deny — all pass
• Linux: unit tests, E2E updater, audit, deny — all pass
• Windows: unit tests, E2E updater — all pass

[FabianLars-crabnebula]

i think getting rid of the cli is good for build times but if we were to keep it (or re-add it later) we could do this

cargo-packager/examples/wails/Packager.toml

Line 9 in 949ec2c

binaries = [{ path = "wails_example", main = true }]

[FabianLars-crabnebula]

Actuallyyyyy, perhaps we should do that since these are examples for users and not just CI? 🤔
For the glibc requirement we could update the runners to 24.04 🤷

[james-crabnebula]

Closing this in favour of a proper fix later. After discussion, the right approach here is target-specific packager config (relates to #360) or $TARGET_OS template variables in binaries-dir, rather than working around the dioxus build system in CI.

Will revisit after the current dependency update work is complete.

[FabianLars-crabnebula]

I'm gonna merge this for the time being with a comment inside so the checks are green again.