Provide a button to clear session data (#231)

Fixes #214

---------

Co-authored-by: graphite-app[bot] <96075541+graphite-app[bot]@users.noreply.github.com>

src/ipc/ipc_client.ts

@@ -821,4 +821,8 @@ export class IpcClient {
   public async renameBranch(params: RenameBranchParams): Promise<void> {
     await this.ipcRenderer.invoke("rename-branch", params);
   }
+
+  async clearSessionData(): Promise<void> {
+    return this.ipcRenderer.invoke("clear-session-data");
+  }
 }