fix: order validation checks by parameter position in stats/base/dists/cauchy/pdf/lib/factory.js

Reorder NaN guards in the factory so checks follow declaration order
`(x0, gamma)`. Behavior unchanged: any matching branch returns
`constantFunction( NaN )`.

Author: claude

lib/node_modules/@stdlib/stats/base/dists/cauchy/pdf/lib/factory.js

@@ -47,8 +47,8 @@ var PI = require( '@stdlib/constants/float64/pi' );
 function factory( x0, gamma ) {
 	var gpi;
 	if (
-		isnan( gamma ) ||
 		isnan( x0 ) ||
+		isnan( gamma ) ||
 		gamma <= 0.0
 	) {
 		return constantFunction( NaN );