fix(e2e): set mtlsMode: disabled on authbridge test fixtures

E2E authbridge tests were failing because the mTLS default changed from
disabled to permissive. The envoy-proxy container crash-looped as the
envoy template now renders TLS contexts by default, but the E2E test
fixtures aren't configured for full mTLS infrastructure.

Set mtlsMode: disabled explicitly on both authbridge-agent and
authbridge-disabled-agent AgentRuntime fixtures to preserve the
existing test behavior. These tests validate sidecar injection, not
mTLS transport.

Signed-off-by: Varsha Prasad Narsing <varshaprasad96@gmail.com>
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>

Author: varshaprasad96

kagenti-operator/test/e2e/fixtures.go

@@ -959,6 +959,7 @@ metadata:
   namespace: ` + authBridgeTestNamespace + `
 spec:
   type: agent
+  mtlsMode: disabled
   targetRef:
     apiVersion: apps/v1
     kind: Deployment
@@ -1092,6 +1093,7 @@ metadata:
   namespace: ` + authBridgeTestNamespace + `
 spec:
   type: agent
+  mtlsMode: disabled
   targetRef:
     apiVersion: apps/v1
     kind: Deployment