Do not sum digits for widget width when some parts are unknown

Closes #14384
(grafted from cd8a0670dd5c6274062e92a40a39509105c800ec)

--HG--
branch : 7.0

sao/src/view/form.js

@@ -2101,7 +2101,7 @@ function eval_pyson(value){
         },
         get width() {
             var digits = this.digits;
-            if (digits) {
+            if (digits && digits.every(d => d !== null)) {
                 return digits.reduce(function(acc, cur) {
                     return acc + cur;
                 });

tryton/tryton/gui/window/view_form/view/form_gtk/float.py

@@ -14,7 +14,7 @@ class Float(Integer):
     @property
     def width(self):
         digits = self.digits
-        if digits:
+        if digits and all(d is not None for d in digits):
             return sum(digits)
         else:
             return self.attrs.get('width', 18)