fix(ngcc): do not warn if paths mapping does not exist (#36525)

In cc4b813e75 the `getBasePaths()`
function was changed to log a warning if a `basePath()` computed from
the `paths` mappings did not exist. It turns out this is a common and
accepted scenario, so we should not log warnings in this case.

Fixes #36518

PR Close #36525

packages/compiler-cli/ngcc/src/entry_point_finder/utils.ts

@@ -50,7 +50,7 @@ export function getBasePaths(
       if (fs.exists(basePath)) {
         basePaths.push(basePath);
       } else {
-        logger.warn(
+        logger.debug(
             `The basePath "${basePath}" computed from baseUrl "${baseUrl}" and path mapping "${
                 path}" does not exist in the file-system.\n` +
             `It will not be scanned for entry-points.`);