Use vectorized flag uuid correctly

Split by commas first, then use the corresponding one for each instance.

Bug: 418796359
Merged-In: I5511f15fd9bcaf149e72609bfa83799505624cbc

Author: jemoreira

base/cvd/cuttlefish/host/commands/assemble_cvd/assemble_cvd_flags.cpp

@@ -229,7 +229,7 @@ DEFINE_vec(
     "with the instance number to support multiple instances");
 
 DEFINE_vec(uuid, CF_DEFAULTS_UUID,
-              "UUID to use for the device. Random if not specified");
+           "UUID to use for the device. Random if not specified");
 DEFINE_vec(daemon, CF_DEFAULTS_DAEMON?"true":"false",
             "Run cuttlefish in background, the launcher exits on boot "
             "completed/failed");

base/cvd/cuttlefish/host/commands/assemble_cvd/flags.cc

@@ -492,6 +492,7 @@ Result<CuttlefishConfig> InitializeCuttlefishConfiguration(
   std::vector<bool> use_sdcard_vec = CF_EXPECT(GET_FLAG_BOOL_VALUE(use_sdcard));
   std::vector<bool> pause_in_bootloader_vec = CF_EXPECT(GET_FLAG_BOOL_VALUE(
       pause_in_bootloader));
+  std::vector<std::string> uuid_vec = CF_EXPECT(GET_FLAG_STR_VALUE(uuid));
   std::vector<bool> daemon_vec = CF_EXPECT(GET_FLAG_BOOL_VALUE(daemon));
   std::vector<bool> enable_minimal_mode_vec = CF_EXPECT(GET_FLAG_BOOL_VALUE(
       enable_minimal_mode));
@@ -1010,7 +1011,7 @@ Result<CuttlefishConfig> InitializeCuttlefishConfiguration(
 
     bool is_any_netsim = is_netsim_all || is_bt_netsim || is_uwb_netsim;
 
-    instance.set_uuid(FLAGS_uuid);
+    instance.set_uuid(uuid_vec[instance_index]);
 
     instance.set_environment_name(environment_name);