[ci] Add Wasm compilation to all_packages web app. (flutter#6981)

Adds a "--wasm" mode to create and build "all_packages" app to verify all our plugins compile with Wasm.

Except not all do for now, so this also adds a "exclude_all_packages_app_wasm.yaml" file that allows us to remove the packages that aren't fully compatible yet.

## Issues

* Fixes: flutter#150748
* Related: flutter#117022
* Related: flutter#148624

Author: ditman

.ci/scripts/create_all_packages_app.sh

@@ -4,5 +4,16 @@
 # found in the LICENSE file.
 set -e
 
+# The base exclusion file for all_packages app.
+exclusions=("script/configs/exclude_all_packages_app.yaml")
+
+# Add a wasm-specific exclusion file if "--wasm" is specified.
+if [[ "$1" == "--wasm" ]]; then
+  exclusions+=",script/configs/exclude_all_packages_app_wasm.yaml"
+fi
+
+# Delete ./all_packages if it exists already
+rm -rf ./all_packages
+
 dart ./script/tool/bin/flutter_plugin_tools.dart create-all-packages-app \
-    --output-dir=. --exclude script/configs/exclude_all_packages_app.yaml
+    --output-dir=. --exclude "$exclusions"

.ci/targets/web_build_all_packages.yaml

@@ -10,3 +10,10 @@ tasks:
   - name: build all_packages app for Web release
     script: .ci/scripts/build_all_packages_app.sh
     args: ["web", "release"]
+  - name: (Wasm) create all_packages app
+    script: .ci/scripts/create_all_packages_app.sh
+    args: ["--wasm"]
+    infra_step: true # Note infra steps failing prevents "always" from running.
+  - name: (Wasm) build all_packages app for Web release
+    script: .ci/scripts/build_all_packages_app.sh
+    args: ["web", "release", "--wasm"]

script/configs/exclude_all_packages_app.yaml

@@ -9,5 +9,5 @@
 # NOTE: camera_android is semi-excluded via special casing in the repo tools.
 # See create_all_packages_app_command.dart.
 
-# This is a permament entry, as it should never be a direct app dependency.
+# This is a permanent entry, as it should never be a direct app dependency.
 - plugin_platform_interface

script/configs/exclude_all_packages_app_wasm.yaml

@@ -0,0 +1,15 @@
+# This list should be kept as short as possible, and things should remain here
+# only as long as necessary, since in general the goal is for all of the latest
+# versions of packages to be mutually compatible, and compilable with Wasm.
+
+# This is only used for wasm compilation. Once all packages in the repo have
+# been migrated, remove this file and use `exclude_all_packages_app.yaml` only.
+
+# Packages that aren't migrated yet.
+# https://github.com/flutter/flutter/issues/117022
+- camera
+- webview_flutter
+
+# Dependencies are not migrated yet
+# https://github.com/flutter/flutter/issues/148624
+- google_maps_flutter