Fix flaky ExportCreateService spec (#4862)

This test expects the requests in the export to be in a particular order,
but no order is applied to the requests passed in and no order is defined
in the ExportCreateService itself, hence the flakiness.

Example failure: https://github.com/rubyforgood/human-essentials/actions/runs/12353561322/job/34472934783#step:7:1433

Author: coalest

spec/services/exports/export_request_service_spec.rb

@@ -237,7 +237,7 @@
       end
 
       it "has expected data for the 3T Diapers request" do
-        expect(subject[1]).to eq([
+        expect(subject).to include([
           request_3t.created_at.strftime("%m/%d/%Y").to_s,
           "Howdy Partner",
           "Child",
@@ -250,7 +250,7 @@
       end
 
       it "has expected data for the 2T Diapers request" do
-        expect(subject[2]).to eq([
+        expect(subject).to include([
           request_2t.created_at.strftime("%m/%d/%Y").to_s,
           "Howdy Partner",
           "Individual",
@@ -263,7 +263,7 @@
       end
 
       it "has expected data for the request with deleted items" do
-        expect(subject[3]).to eq([
+        expect(subject).to include([
           request_with_deleted_items.created_at.strftime("%m/%d/%Y").to_s,
           "Howdy Partner",
           nil,
@@ -276,7 +276,7 @@
       end
 
       it "has expected data for the request with multiple items" do
-        expect(subject[4]).to eq([
+        expect(subject).to include([
           request_with_multiple_items.created_at.strftime("%m/%d/%Y").to_s,
           "Howdy Partner",
           nil,
@@ -289,7 +289,7 @@
       end
 
       it "has expected data for the request with 4T diapers without pack unit" do
-        expect(subject[5]).to eq([
+        expect(subject).to include([
           request_4t.created_at.strftime("%m/%d/%Y").to_s,
           "Howdy Partner",
           "Quantity",
@@ -302,7 +302,7 @@
       end
 
       it "has expected data for the request with 4T diapers with pack unit" do
-        expect(subject[6]).to eq([
+        expect(subject).to include([
           request_4t_pack.created_at.strftime("%m/%d/%Y").to_s,
           "Howdy Partner",
           "Quantity",