Bump protobuf to 44ecd7424fa0a9e023ecac0d894f50926ed111cf

Changes:
```
> git log --format="%C(auto) %h %s" 4916e6f..44ecd74
 https://dart.googlesource.com/protobuf.git/+/44ecd74 Sync JSON web decoders (1028)
 https://dart.googlesource.com/protobuf.git/+/f7f65d4 CI: Also run plugin tests on Chrome, with dart2js and dart2wasm (1031)
 https://dart.googlesource.com/protobuf.git/+/048fdc5 CI: Run all of the checks on every change (1032)
 https://dart.googlesource.com/protobuf.git/+/33b782f Remove monorepo (1030)
 https://dart.googlesource.com/protobuf.git/+/4c842a7 Make PbFieldType members public (1027)
 https://dart.googlesource.com/protobuf.git/+/7f7d776 Split protobuf package into libraries (1026)

```

Diff: https://dart.googlesource.com/protobuf.git/+/4916e6f7d34443869c27d997749d4362870fd7ce..44ecd7424fa0a9e023ecac0d894f50926ed111cf/
Tested: test expectations updated for the new protobuf version
Change-Id: I85adf2631f171545394e429b174007c26ec52340
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/442920
Auto-Submit: Devon Carew <[email protected]>
Commit-Queue: Ömer Ağacan <[email protected]>
Reviewed-by: Ömer Ağacan <[email protected]>

Author: devoncarew

DEPS

@@ -141,7 +141,7 @@ vars = {
   "leak_tracker_rev": "f5620600a5ce1c44f65ddaa02001e200b096e14c", # rolled manually
   "material_color_utilities_rev": "799b6ba2f3f1c28c67cc7e0b4f18e0c7d7f3c03e",
   "native_rev": "768a06d7bf34d84ea4ac8fc38bf8cf1d9afb5779", # rolled manually while native assets are experimental
-  "protobuf_rev": "4916e6f7d34443869c27d997749d4362870fd7ce",
+  "protobuf_rev": "44ecd7424fa0a9e023ecac0d894f50926ed111cf",
   "pub_rev": "c3e50919d11896f014cb971e1776d00a0e2d18b3", # rolled manually
   "shelf_rev": "082d3ac2d13a98700d8148e8fad8f3e12a6fd0e1",
   "sync_http_rev": "c07f96f89a7eec7e3daac641fa6c587224fcfbaa",