ENH: Add support to pass a prefix for hyperparam args (#936)

When `hyperparam_args` is passed, the command is modified to add the
argument in the settings. For example, if the looks like
`{learning_rate: [1, 2, 3]}`, something like
`--learning_rate=${{inputs.learning_rate}}` will be added to the
command. But sometimes we wouldn't want the dashes, e.g., when using
Hydra (`learning_rate=${{inputs.learning_rate}}` or maybe
`+learning_rate=${{inputs.learning_rate}}`). This PR adds support to
specify the prefix for the argument (default: `"--"`). For Hydra, we
might want, e.g., `""` or `"+"`.

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hi-ml-azure/src/health_azure/himl.py

@@ -419,6 +419,7 @@ def submit_run_v2(
     pytorch_processes_per_node: Optional[int] = None,
     use_mpi_run_for_single_node_jobs: bool = True,
     display_name: Optional[str] = None,
+    hyperdrive_argument_prefix: str = "--",
 ) -> Job:
     """
     Starts a v2 AML Job on a given workspace by submitting a command
@@ -452,6 +453,9 @@ def submit_run_v2(
         This is required for Kubernetes compute. If False, single node jobs will not be run as distributed jobs.
     :param display_name: The name for the run that will be displayed in the AML UI. If not provided, a random
         display name will be generated by AzureML.
+    :param: hyperdrive_argument_prefix: Prefix to add to hyperparameter arguments. Some examples might be "--", "-"
+        or "". For example, if "+" is used, a hyperparameter "learning_rate" with value 0.01 will be passed as
+        `+learning_rate=0.01`.
     :return: An AzureML Run object.
     """
     root_dir = sanitize_snapshoot_directory(snapshot_root_directory)
@@ -512,7 +516,7 @@ def create_command_job(cmd: str) -> Command:
 
         for sample_param, choices in param_sampling.items():
             input_datasets_v2[sample_param] = choices.values[0]
-            cmd += f" --{sample_param}=" + "${{inputs." + sample_param + "}}"
+            cmd += f" {hyperdrive_argument_prefix}{sample_param}=" + "${{inputs." + sample_param + "}}"
 
         command_job = create_command_job(cmd)
 
@@ -744,6 +748,7 @@ def submit_to_azure_if_needed(  # type: ignore
     use_mpi_run_for_single_node_jobs: bool = False,
     display_name: Optional[str] = None,
     entry_command: Optional[PathOrString] = None,
+    hyperdrive_argument_prefix: str = "--",
 ) -> AzureRunInfo:  # pragma: no cover
     """
     Submit a folder to Azure, if needed and run it.
@@ -819,6 +824,9 @@ def submit_to_azure_if_needed(  # type: ignore
         Setting this flag to True is required Kubernetes compute.
     :param display_name: The name for the run that will be displayed in the AML UI. If not provided, a random
         display name will be generated by AzureML.
+    :param: hyperdrive_argument_prefix: Prefix to add to hyperparameter arguments. Some examples might be "--", "-"
+        or "". For example, if "+" is used, a hyperparameter "learning_rate" with value 0.01 will be passed as
+        `+learning_rate=0.01`.
     :return: If the script is submitted to AzureML then we terminate python as the script should be executed in AzureML,
         otherwise we return a AzureRunInfo object.
     """
@@ -986,6 +994,7 @@ def submit_to_azure_if_needed(  # type: ignore
                 num_nodes=num_nodes,
                 pytorch_processes_per_node=pytorch_processes_per_node_v2,
                 use_mpi_run_for_single_node_jobs=use_mpi_run_for_single_node_jobs,
+                hyperdrive_argument_prefix=hyperdrive_argument_prefix,
             )
 
             if after_submission is not None: