Record PDS error responses in Sentry

This makes it easier to debug issues by including a breadcrumb
containing the response from PDS in Sentry.

app/lib/nhs/pds.rb

@@ -32,6 +32,8 @@ def get_patient(nhs_number)
         "personal-demographics/FHIR/R4/Patient/#{nhs_number}"
       )
     rescue Faraday::BadRequestError => e
+      add_sentry_breadcrumb(e)
+
       if is_error?(e, "INVALID_RESOURCE_ID")
         raise InvalidNHSNumber, nhs_number
       else
@@ -56,10 +58,23 @@ def search_patients(attributes)
         "personal-demographics/FHIR/R4/Patient",
         attributes
       )
+    rescue Faraday::BadRequestError => e
+      add_sentry_breadcrumb(e)
+      raise
     end
 
     private
 
+    def add_sentry_breadcrumb(error)
+      crumb =
+        Sentry::Breadcrumb.new(
+          category: "http.response",
+          data: error.response,
+          level: "error"
+        )
+      Sentry.add_breadcrumb(crumb)
+    end
+
     def is_error?(error, code)
       response = JSON.parse(error.response_body)