feat: Add support for per-context summary events. (#245)

Updates the common dependency to 1.8.0 to support per-context summary
events.

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Low Risk**
> Single dependency version bump with no local logic changes; risk is
limited to behavior changes introduced by the updated shared library.
> 
> **Overview**
> Bumps `packages/common_client` dependency on
`launchdarkly_dart_common` from `1.6.1` to `1.8.0` to pick up newer
shared functionality (notably per-context summary event support).
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
6edaba2. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: kinyoklion

packages/common_client/pubspec.yaml

@@ -9,7 +9,7 @@ environment:
 
 dependencies:
   http: ^1.1.2
-  launchdarkly_dart_common: 1.6.1
+  launchdarkly_dart_common: 1.8.0
   launchdarkly_event_source_client: 2.0.1
   crypto: ^3.0.3
   uuid: ">= 3.0.7 <5.0.0"