deps: Upgrade Flutter to latest main, 3.18.0-18.0.pre.10

And update Flutter's supporting libraries to match.

Author: gnprice

pubspec.lock

@@ -664,18 +664,26 @@ packages:
     dependency: transitive
     description:
       name: leak_tracker
-      sha256: "04be76c4a4bb50f14904e64749237e541e7c7bcf7ec0b196907322ab5d2fc739"
+      sha256: e45c31f458d01fd9ef4a214feb2e153b72d5b1907435f4332b1637a2f348c021
       url: "https://pub.dev"
     source: hosted
-    version: "9.0.16"
+    version: "9.0.18"
+  leak_tracker_flutter_testing:
+    dependency: transitive
+    description:
+      name: leak_tracker_flutter_testing
+      sha256: "54808cfcfa87dbc0d74c61ac063d624adf1bd5c0407301f32b06c783c60dc4ca"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.0.0"
   leak_tracker_testing:
     dependency: transitive
     description:
       name: leak_tracker_testing
-      sha256: b06739349ec2477e943055aea30172c5c7000225f79dad4702e2ec0eda79a6ff
+      sha256: "7e71be3c161472f6c9158ac8875dd8de575060d60b5d159ebca3600ea32c9116"
       url: "https://pub.dev"
     source: hosted
-    version: "1.0.5"
+    version: "1.0.6"
   lints:
     dependency: transitive
     description:
@@ -696,10 +704,10 @@ packages:
     dependency: transitive
     description:
       name: matcher
-      sha256: "1803e76e6653768d64ed8ff2e1e67bea3ad4b923eb5c56a295c3e634bad5960e"
+      sha256: d2323aa2060500f906aa31a895b4030b6da3ebdcc5619d14ce1aada65cd161cb
       url: "https://pub.dev"
     source: hosted
-    version: "0.12.16"
+    version: "0.12.16+1"
   material_color_utilities:
     dependency: transitive
     description:
@@ -1282,5 +1290,5 @@ packages:
     source: hosted
     version: "3.1.2"
 sdks:
-  dart: ">=3.3.0-212.0.dev <4.0.0"
-  flutter: ">=3.18.0-7.0.pre.55"
+  dart: ">=3.3.0-244.0.dev <4.0.0"
+  flutter: ">=3.18.0-18.0.pre.10"

pubspec.yaml

@@ -24,8 +24,8 @@ environment:
   # that by the time we want to release, these will have become stable.
   # TODO: Before general release, switch to stable Flutter and Dart versions,
   #   or pin exact versions: https://github.com/zulip/zulip-flutter/issues/15
-  sdk: '>=3.3.0-212.0.dev <4.0.0'
-  flutter: '>=3.18.0-7.0.pre.55'
+  sdk: '>=3.3.0-244.0.dev <4.0.0'
+  flutter: '>=3.18.0-18.0.pre.10'
 
 # Dependencies specify other packages that your package needs in order to work.
 # To automatically upgrade your package dependencies to the latest versions