Restricted members importer to ignore "products" column

refs https://github.com/TryGhost/Team/issues/1076
refs TryGhost/Ghost@fe754cc#diff-b67ecda91b5bd79c598e5c5a9ec2ccf28dbfab6a924b21352273865e07cd7ceaR57

- The "products" column has not been doing any logic anything since at least 5.20.0 (see refed commit). The concept of columns in the export file was mostly there for analytical/data filtering reasons - so the user could analyze their exports. CSV was never a good suite for relational data that "products" (or now tiers) represent
- The "tiers" column will still be present in the exported CSV file, but there is not going to be any logic attached to it.
- The only columns that can effect the "tiers" state of the member are: "complimentary_plan" (assign default tier to the member) and "stripe_customer_id" (pulls in subscription/tier data from Stripe)

Author: naz

packages/members-csv/lib/parse.js

@@ -29,12 +29,6 @@ module.exports = (path, headerMapping, defaultLabels = []) => {
                     }
                 }
 
-                if (header === 'products') {
-                    if (value && typeof value === 'string') {
-                        return value.split(',').map(name => ({name}));
-                    }
-                }
-
                 if (header === 'subscribed') {
                     return value.toLowerCase() !== 'false';
                 }

packages/members-csv/test/unparse.test.js

@@ -87,7 +87,7 @@ [email protected],"banana, avocado"`;
         assert.equal(result, expected);
     });
 
-    it('handles the tiers to products property serialization', function () {
+    it('handles the tiers property serialization', function () {
         const json = [{
             email: '[email protected]',
             tiers: [{