Auto merge of #27316 - asajeffrey:webxr-save-restore-gl-state, r=Manishearth

Save / restore state when updating opaque framebuffer bindings

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This saves and restores the WebGL bindings for texture and framebuffer when beginning a webxr frame.

---
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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #27286
- [x] These changes do not require tests because we don't reftest hololens (it would be nice if we did!)

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Cargo.lock

@@ -6790,7 +6790,7 @@ dependencies = [
 [[package]]
 name = "webxr"
 version = "0.0.1"
-source = "git+https://github.com/servo/webxr#3e731eac4180f739e85f8b6b9dacbc5a2015aec8"
+source = "git+https://github.com/servo/webxr#53c07f787d882c1b0dede5f4bb645a3bcf38d676"
 dependencies = [
  "android_injected_glue",
  "bindgen",
@@ -6813,7 +6813,7 @@ dependencies = [
 [[package]]
 name = "webxr-api"
 version = "0.0.1"
-source = "git+https://github.com/servo/webxr#3e731eac4180f739e85f8b6b9dacbc5a2015aec8"
+source = "git+https://github.com/servo/webxr#53c07f787d882c1b0dede5f4bb645a3bcf38d676"
 dependencies = [
  "euclid",
  "ipc-channel",