[build] Override dh_shlibdeps' determination of the libc version needed.

There is no libc.pc in the sysroot.

TEST=host newer than jammy
Change-Id: Ia8ce4edf4a6587bb229b4cc87b72b13f026613d0
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/434940
Reviewed-by: Alexander Thomas <[email protected]>
Commit-Queue: Alexander Thomas <[email protected]>

Author: rmacnak-google

tools/debian_package/debian/control

@@ -7,5 +7,5 @@ Build-Depends: python3:native
 
 Package: dart
 Architecture: any
-Depends: ${shlibs:Depends}, ${misc:Depends}
+Depends: ${misc:Depends}, libc6 (>= 2.31)
 Description: Dart SDK