gpui: Use platform clock in action profiler (#63183)

# Objective

I’m building a component library with GPUI and ran into a panic when I
enabled the profiler feature for a `wasm32-unknown-unknown` build.
Dispatching an action calls std::time::Instant::now(), which has no
clock implementation on this target, and the browser reports time not
implemented on this platform. The panic then triggers RefCell already
borrowed errors and leaves the GPUI window unresponsive.

The current `main` fails to compile this feature combination because the
action profiler’s std::time::Instant does not match the scheduler-based
timestamps in the profiler journal. I want GPUI’s action profiler to use
the same cross-platform clock as the rest of the profiler and keep this
configuration covered by CI.

## Solution

Use `scheduler::Instant`, the scheduler crate's cross-platform instant
type, for action timings so they match the rest of the GPUI profiler.
Keep the existing downstream wasm check and add a separate
profiler-enabled GPUI wasm check so CI covers both feature
configurations.

## Testing

- `cargo check --target wasm32-unknown-unknown -p gpui
--no-default-features --features profiler`
- `cargo -Zbuild-std=std,panic_abort check --target
wasm32-unknown-unknown -p gpui_platform -p cloud_api_client --features
gpui/profiler`
- `cargo test -p gpui --no-default-features --features profiler
profiler::` (48 tests passed)
- `./script/clippy -p gpui`

I ran a wasm GPUI app in Edge with WebGPU. The app opens a window and
dispatches an action with `profiler` enabled. Before this change, the
action produced the clock panic and follow-on borrow errors. After the
fix change, the action completed and the window remained active.

I did not run the browser harness in Firefox or Safari, though the wasm
compile check covers the changed profiler configuration without
depending on a browser.

## Self-Review Checklist:

- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content adheres to Zed's UI standards
([UX/UI](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
and
[icon](https://github.com/zed-industries/zed/blob/main/crates/icons/README.md)
guidelines); this PR has no UI changes
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

---

Release Notes:

- Fixed a crash when dispatching profiled GPUI actions in web
applications.

---------

Co-authored-by: Anthony Eid <anthony@zed.dev>

crates/gpui/src/profiler/actions.rs

@@ -1,6 +1,7 @@
-use std::time::{Duration, Instant};
+use std::time::Duration;
 
 use itertools::Itertools;
+use scheduler::Instant;
 
 #[cfg(feature = "profiler")]
 use crate::action::Action;