chore (provider-utils): update eventsource-parser to 3.0.3 (#6869)

## Background

Build issues with Metro were reported in #6862 . They were caused by the
`eventsource-parser` package, which subsequently was updated to 3.0.3
with a fix.

## Summary

Require `eventsource-parser` 3.0.3 or newer.
 
## Related Issues

Fixes #6862

Author: lgrammel

.changeset/dirty-dolphins-march.md

@@ -0,0 +1,5 @@
+---
+'@ai-sdk/provider-utils': patch
+---
+
+chore (provider-utils): update eventsource-parser to 3.0.3

packages/provider-utils/package.json

@@ -42,7 +42,7 @@
     "@ai-sdk/provider": "workspace:*",
     "@standard-schema/spec": "^1.0.0",
     "zod-to-json-schema": "^3.24.1",
-    "eventsource-parser": "^3.0.2"
+    "eventsource-parser": "^3.0.3"
   },
   "devDependencies": {
     "@types/node": "20.17.24",