Fix test_shell_command_interruption flake (#10649)

## Human summary
Sandboxing (specifically `LandlockRestrict`) is means that e.g. `sleep
10` fails immediately. Therefore it cannot be interrupted.

In suite::interrupt::test_shell_command_interruption, sleep 10 is issued
at 17:28:16.554 (ToolCall: shell_command {"command":"sleep 10"...}),
then fails at 17:28:16.589 with duration_ms=34, success=false,
exit_code=101, and
    Sandbox(LandlockRestrict).

## Codex summary
- set `sandbox_mode = "danger-full-access"` in `interrupt` and
`v2/turn_interrupt` integration tests
- set `sandbox: Some(SandboxMode::DangerFullAccess)` in
`test_codex_jsonrpc_conversation_flow`
- set `sandbox_policy: Some(SandboxPolicy::DangerFullAccess)` in
`command_execution_notifications_include_process_id`

## Why
On some Linux CI environments, command execution fails immediately with
`LandlockRestrict` when sandboxed. These tests are intended to validate
JSON-RPC/task lifecycle behavior (interrupt semantics, command
notification shape/process id, request flow), but early sandbox startup
failure changes turn flow and can trigger extra follow-up requests,
causing flakes.

This change removes environment-specific sandbox startup dependency from
these tests while preserving their primary intent.

## Testing
- not run in this environment (per request)

codex-rs/app-server/tests/suite/interrupt.rs

@@ -147,7 +147,7 @@ fn create_config_toml(codex_home: &Path, server_uri: String) -> std::io::Result<
             r#"
 model = "mock-model"
 approval_policy = "never"
-sandbox_mode = "read-only"
+sandbox_mode = "danger-full-access"
 
 model_provider = "mock_provider"