cargo: Remove ashpd's gtk4 feature

It is not actually used.

Cargo.lock

@@ -149,9 +149,6 @@ dependencies = [
  "enumflags2",
  "futures-channel",
  "futures-util",
- "gdk4-wayland",
- "gdk4-x11",
- "gtk4",
  "libc",
  "once_cell",
  "pipewire",
@@ -1764,30 +1761,6 @@ dependencies = [
  "system-deps",
 ]
 
-[[package]]
-name = "gdk4-wayland"
-version = "0.7.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0db9102ff11e55bd65e153c1192abc21ddfa45ede90622e423d4e4a0e5d5f313"
-dependencies = [
- "gdk4",
- "gdk4-wayland-sys",
- "gio",
- "glib",
- "libc",
-]
-
-[[package]]
-name = "gdk4-wayland-sys"
-version = "0.7.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d48159be256ae0212d5a2b9884627197d08082c7168b28775b53a0f9885d5624"
-dependencies = [
- "glib-sys",
- "libc",
- "system-deps",
-]
-
 [[package]]
 name = "gdk4-win32"
 version = "0.7.2"
@@ -1815,31 +1788,6 @@ dependencies = [
  "system-deps",
 ]
 
-[[package]]
-name = "gdk4-x11"
-version = "0.7.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "28c9bbf8ea1ea8469e74c3fdfafc142c9e14810a27f89ddb01b5e9076a60a450"
-dependencies = [
- "gdk4",
- "gdk4-x11-sys",
- "gio",
- "glib",
- "libc",
-]
-
-[[package]]
-name = "gdk4-x11-sys"
-version = "0.7.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a3de1709370758192369f5329aa593847797f1c693c95e8a261e9b2e06a5f125"
-dependencies = [
- "gdk4-sys",
- "glib-sys",
- "libc",
- "system-deps",
-]
-
 [[package]]
 name = "generic-array"
 version = "0.14.7"

Cargo.toml

@@ -22,7 +22,6 @@ codegen-units = 16
 # Please keep dependencies sorted.
 [dependencies]
 ashpd = { version = "0.6", default-features = false, features = [
-    "gtk4",
     "pipewire",
     "tracing",
     "tokio",