bump(carta-investors): 78793217 → 1b6e78b4 (#3552)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

.claude-plugin/marketplace.json

@@ -599,7 +599,7 @@
         "url": "https://github.com/carta/plugins.git",
         "path": "plugins/carta-investors",
         "ref": "main",
-        "sha": "787932173c1bc0fb6f2346e380fddd2349ceb8df"
+        "sha": "1b6e78b4682160975952f4d2c90a81493cd4c7d0"
       },
       "homepage": "https://carta.com"
     },