[dynamic modules] Add dart:core to dynamic interface by default

In order to simplify creating dynamic interface yaml files,
the following is added to dynamic interface by default:

callable: dart:core, pragma._
extendable: Object

TEST=pkg/dynamic_modules/test

CoreLibraryReviewExempt: no API changes, only adding pragmas
Change-Id: I925532c4c024ebbcf4972b00be0e0a080d5878fa
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/422024
Reviewed-by: Sigmund Cherem <sigmund@google.com>
Commit-Queue: Alexander Markov <alexmarkov@google.com>

https://dart.googlesource.com/sdk/+/1c429e9f36a3e094d44710f11364df2ab0d4ff2a
diff --git a/DEPS b/DEPS
index 321cd89..7b1dc79 100644
--- a/DEPS
+++ b/DEPS
@@ -238,7 +238,7 @@
 ]
 
 deps = {
-  'flutter/engine/src/flutter/third_party/dart': Var('dart_git') + '/sdk' + '@' + '23c8a119c257c33082c9d70ffafc136a4ff98fd1',
+  'flutter/engine/src/flutter/third_party/dart': Var('dart_git') + '/sdk' + '@' + '1c429e9f36a3e094d44710f11364df2ab0d4ff2a',
 
   'flutter': Var('flutter_git') + '/mirrors/flutter' + '@' + 'b9e982614b6bb53fe71baff5aabf5845185e2fb8',
 
diff --git a/commits.json b/commits.json
index 2d8195a..774c2cc 100644
--- a/commits.json
+++ b/commits.json
@@ -1,4 +1,4 @@
 {
   "flutter":"b9e982614b6bb53fe71baff5aabf5845185e2fb8",
-  "flutter/engine/src/flutter/third_party/dart":"23c8a119c257c33082c9d70ffafc136a4ff98fd1"
+  "flutter/engine/src/flutter/third_party/dart":"1c429e9f36a3e094d44710f11364df2ab0d4ff2a"
 }
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