Remove restriction on generate_pdb_file to be only used in dbg and fastbuild mode

Users may want to build in opt mode and still want the pdb file to be a linking action output.
See https://github.com/bazelbuild/rules_cc/issues/94#issuecomment-828254895

RELNOTES: None
PiperOrigin-RevId: 372351216
diff --git a/tools/cpp/windows_cc_toolchain_config.bzl b/tools/cpp/windows_cc_toolchain_config.bzl
index 042d519..f43f8ba 100644
--- a/tools/cpp/windows_cc_toolchain_config.bzl
+++ b/tools/cpp/windows_cc_toolchain_config.bzl
@@ -666,10 +666,6 @@
 
         generate_pdb_file_feature = feature(
             name = "generate_pdb_file",
-            requires = [
-                feature_set(features = ["dbg"]),
-                feature_set(features = ["fastbuild"]),
-            ],
         )
 
         output_execpath_flags_feature = feature(