fix: don't insert 0 at start or end of attribute if whitespace (#2036)

docs/03-plugins/cleanupNumericValues.mdx

@@ -18,4 +18,4 @@ svgo:
       default: true
 ---
 
-Rounds numeric values, and removes the unit when it's `px` as this is the default.
+Rounds numeric values, removes the unit when it's `px` as this is the default, and removes redundant spaces around and between numbers.

plugins/cleanupNumericValues.js

@@ -39,6 +39,7 @@ export const fn = (_root, params) => {
         if (node.attributes.viewBox != null) {
           const nums = node.attributes.viewBox.split(/\s,?\s*|,\s*/g);
           node.attributes.viewBox = nums
+            .filter((value) => value.length != 0)
             .map((value) => {
               const num = Number(value);
               return Number.isNaN(num)
@@ -54,7 +55,7 @@ export const fn = (_root, params) => {
             continue;
           }
 
-          const match = value.match(regNumericValues);
+          const match = regNumericValues.exec(value);
 
           // if attribute value matches regNumericValues
           if (match) {

test/plugins/cleanupNumericValues.03.svg.txt

@@ -0,0 +1,5 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox=" 0 0      150 100 "/>
+
+@@@
+
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 150 100"/>