Use load() rather than preload() for terminal icon

Allows the plugin to load even if resources have not been imported yet.
For example, if someone has opened a project with the plugin for the
first time. Otherwise, the plugin will fail to load and be disable in
the `project.godot` file.

.github/workflows/main.yml

@@ -185,11 +185,7 @@ jobs:
         path: addons/godot_xterm/native/bin
     - name: Import assets
       shell: bash
-      # The GodotXterm plugin will be disabled the first time we run the editor as resources that it depends
-      # (e.g. icons) will not have been imported yet so the plugin will fail to load. Without the plugin
-      # enabled resources imported by GodotXterm import plugins (e.g. .cast) will not be imported. Therefore,
-      # we need to re-enable the plugin by checking out project.godot and running the editor again.
-      run: godot --editor .github/import_assets.tscn && git checkout project.godot && godot --editor .github/import_assets.tscn
+      run: godot --editor .github/import_assets.tscn
     - name: Export HTML5
       run: godot --no-window --export HTML5
     - name: NPM cache

addons/godot_xterm/plugin.gd

@@ -18,7 +18,9 @@ func _enter_tree():
 	add_custom_type("Asciicast", "Animation", asciicast_script, null)
 
 	var terminal_script = preload("./terminal.gd")
-	var terminal_icon = preload("./nodes/terminal/terminal_icon.svg")
+	var terminal_icon = load(
+		"%s/nodes/terminal/terminal_icon.svg" % get_script().resource_path.get_base_dir()
+	)
 	add_custom_type("Terminal", "Control", terminal_script, terminal_icon)
 
 	if pty_supported: