CodeableConcept.coding.display and extension.valueString is trimming leading and trailing spaces

Describe the bug
Save a fhir resource having codeableConcept: coding and extension objects with leading and trailing spaces as shown below:

"code": {
"coding": [
{
"extension": [
{
"url": "http://test.com/AVALUE"
, "valueString": " SOME VALUE "
}
],
"system": "http://test.com/DR/Code"
, "code": "SOMECODE",
"display": " SOME DESCRIPTION "
}
}

Retrieve the fhir resource having this codeableConcept, the values are trimmed for extension.valueString and Coding.display
"coding": [
{
"extension": [
{
"url": "http://test.com/AVALUE"
, "valueString": "SOME VALUE"
}
],
"system": "http://test.com/DR/Code"
, "code": "SOMECODE",
"display": "SOME DESCRIPTION"
}
}

FHIR Version?
R4

To Reproduce
Steps to reproduce the behavior:

1. Create a resource with Codeable concept.
2. Add some leading and trailing spaces for coding.display and coding.extension.valueString field.
3. Save fhir resource.
4. retrieve the fhir resource back.

Expected behavior
The Coding.display and extension.valueString should retain trailing and leading spaces.

Actual behavior
coding.extension.valueString and coding.display values are trimmed.

AB#119105

Start by reproducing an R4 resource round trip using CodeableConcept.coding.display and extension.valueString with leading and trailing spaces. Trace where those values are changed during save and retrieval; done means both fields retain the original spaces after retrieval.