ReferencedResourceNotProvisioned: DataPrivateSubnet is not in Succeeded state

:white_check_mark: Checklist

[x] I have searched open and closed issues for duplicates.
[x] This is a problem observed when deploying a Data Safe Haven.
[x] I can reproduce this with the latest version.
[x] I have read through the documentation.
[x] This isn't an open-ended question (open a discussion if it is).

:computer: System information

Operating System:
Data Safe Haven version: 5.0.1

:package: Packages

List of packages

```none Paste list of packages here ```

:no_entry_sign: Describe the problem

:deciduous_tree: Log messages

Relevant log messages

```none Diagnostics: azure-native:network:PrivateEndpoint (sre_data_storage_account_data_private_sensitive_private_endpoint): error: 1 error occurred: * Code="RetryableError" Message="A retryable error occurred." Details=[{"code":"ReferencedResourceNotProvisioned","message":"Cannot proceed with operation because resource /subscriptions/07733781-3909-45a2-86f3-4f717505f4ef/resourceGroups/shm-prod5-sre-test-t2-hdl-rg/providers/Microsoft.Network/virtualNetworks /shm-prod5-sre-test-t2-hdl-vnet/subnets/DataPrivateSubnet used by resource /subscriptions/07733781-3909-45a2-86f3-4f717505f4ef/resourceGroups/shm-prod5-sre-test-t2-hdl-rg/providers/Microsoft.Network/networkInterfac es/shm-prod5-sre-test-t2-hdl-pep-storage-accou.nic.0d79bc26-0c85-47fc-9516-7c783a72c0b3 is not in Succeeded state. Resource is in Updating state and the last operation that updated/is updating the resource is PutSubnetOperation."}] pulumi:pulumi:Stack (data-safe-haven-shm-prod5-sre-test-t2-hdl): WARNING: All log messages before absl::InitializeLog() is called are written to STDERR I0000 00:00:1730196963.771893 16813007 fork_posix.cc:77] Other threads are currently calling into gRPC, skipping fork() handlers I0000 00:00:1730196963.799456 16813007 fork_posix.cc:77] Other threads are currently calling into gRPC, skipping fork() handlers I0000 00:00:1730197054.512867 16816138 fork_posix.cc:77] Other threads are currently calling into gRPC, skipping fork() handlers I0000 00:00:1730197055.114869 16816138 fork_posix.cc:77] Other threads are currently calling into gRPC, skipping fork() handlers I0000 00:00:1730197107.264491 16816138 fork_posix.cc:77] Other threads are currently calling into gRPC, skipping fork() handlers I0000 00:00:1730197107.872033 16816138 fork_posix.cc:77] Other threads are currently calling into gRPC, skipping fork() handlers error: update failed Resources: + 141 created Duration: 11m46s Pulumi error: + azure-native:network:PrivateEndpoint sre_data_storage_account_data_private_sensitive_private_endpoint creating (26s) error: 1 error occurred: Pulumi error: + azure-native:network:PrivateEndpoint sre_data_storage_account_data_private_sensitive_private_endpoint **creating failed** error: 1 error occurred: Pulumi error: + pulumi:pulumi:Stack data-safe-haven-shm-prod5-sre-test-t2-hdl creating (700s) error: update failed Pulumi error: error: 1 error occurred: Pulumi error: error: update failed Pulumi error: stderr: Pulumi update failed. Pulumi deployment failed. Could not deploy Secure Research Environment 'test_t2_hdl'. ```

alan-turing-institute / data-safe-haven