Make conditional_create_duplicate_identifiers_enabled default true if partitioning is enabled

[esecules]

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Describe the issue
One of the requirements for data partitioning and multitennancy is that one tenant's data cannot affect another tenant. However the default setting: conditional_create_duplicate_identifiers_enabled=false means that Resource identifiers must be globally unique across tenants (see error message below). This is not expected when partitioning is enabled. I propose that this setting is default true when partitioning is enabled so that identifiers from separate tenants can have the same values. I might go one step further to suggest that this setting is not needed at the top level as I cannot see a case where we would want to set it to true or false independently of enabling or disabling partitioning as a whole.

Environment (please complete the following information):

• HAPI FHIR Version
• OS: [e.g. iOS]
• Browser [e.g. chrome, safari]

Additional context
The default configuration for partitioning produces this error log when I run my partitioning tests that create two identical resources in two separate tenants. I would expect that partitioning works by default.

ERROR: duplicate key value violates unique constraint \"hfj_res_search_url_pkey\"\n  Detail: Key (res_search_url, partition_id)=(Patient?identifier=1_76, -1) already exists.

[esecules]

relates to the setting added in #5983 to fix the bug #6033