fix: make feature strings more robust to whitespace (#15602)

Fixes #15594

lib/common/parse-features-string.js

@@ -4,12 +4,12 @@
 // - `features` input string
 // - `emit` function(key, value) - called for each parsed KV
 module.exports = function parseFeaturesString (features, emit) {
-  features = `${features}`
+  features = `${features}`.trim()
   // split the string by ','
-  features.split(/,\s*/).forEach((feature) => {
+  features.split(/\s*,\s*/).forEach((feature) => {
     // expected form is either a key by itself or a key/value pair in the form of
     // 'key=value'
-    let [key, value] = feature.split(/\s*=/)
+    let [key, value] = feature.split(/\s*=\s*/)
     if (!key) return
 
     // interpret the value as a boolean, if possible