Omit expression and detail elements from OperationOutcome issues with no meaningful value

[lmsurpre]

Is your feature request related to a problem? Please describe.
While doing QA on #2050 I noted that our OperationOutcome.Issue has a expression like <empty>:
#2050 (comment)

This is coming from our FHIRUtil.buildOperationOutcomeIssue implementations.
If you call a different variant instead, you can end up with details like <no details> AND an expression like <no expression>.

I don't think these placeholder values have much value and, in fact, including elements which have no value sort of run contrary to the methodology/philosophy in FHIR. For example, from https://www.hl7.org/fhir/json.html#xml

Just as in XML, JSON objects and arrays are never empty, and properties never have null values (except for a special case documented below). Omit a property if it is empty

Describe the solution you'd like
Update all variants of FHIRUtil.buildOperationOutcomeIssue to omit the expression (and details) elements when we have no value for these.

We already do this for a lot of our OperationOutcome issues... I think its just the ones that call FHIRUtil.buildOperationOutcomeIssue which do this.

Describe alternatives you've considered

Acceptance Criteria

1. GIVEN [a precondition]
   AND [another precondition]
   WHEN [test step]
   AND [test step]
   THEN [verification step]
   AND [verification step]

Additional context
Similar but different from #2596 which was closed as wontfix

QA suggestion
Test PUT with IfNoneMatch header set to * with existing version 1 of resource existing to verify the 412 error with an OperationOutcome->Issues->Expression does not contain '' value.

[lmsurpre]

I ran the suggested test and confirmed that the OperationOutcome no longer contains <no expression>.

{
	"resourceType": "OperationOutcome",
	"id": "7f-0-0-1-8c5833d9-ac98-400e-8c8b-ce7cea5f130e",
	"issue": [
		{
			"severity": "fatal",
			"code": "conflict",
			"details": {
				"text": "IfNoneMatch precondition failed."
			}
		}
	]
}

I also forced a couple other error responses and never saw the <no expression> or <no details> text.