fix(resolve): Check val not nil in resolve funcs (#2097)

We did not check `val ~= nil` in the resolve functions, so config like
`{ nil, max = 30 }` will throw a nil error. Also, if the config is `{
padding = _ }`, the logic relies on the function handling the padding is
iterated before the one handling min/max in the map, which is not always
guaranteed.

Fix the bug by adding nil check in the function handling min/max. Close

lua/telescope/config/resolve.lua

@@ -139,7 +139,7 @@ end] = function(_, val)
 end
 
 _resolve_map[function(val)
-  return type(val) == "table" and val[1] >= 0 and val[1] < 1 and val["max"] ~= nil
+  return type(val) == "table" and val["max"] ~= nil and val[1] ~= nil and val[1] >= 0 and val[1] < 1
 end] =
   function(selector, val)
     return function(...)
@@ -149,7 +149,7 @@ end] =
   end
 
 _resolve_map[function(val)
-  return type(val) == "table" and val[1] >= 0 and val[1] < 1 and val["min"] ~= nil
+  return type(val) == "table" and val["min"] ~= nil and val[1] ~= nil and val[1] >= 0 and val[1] < 1
 end] =
   function(selector, val)
     return function(...)