java_sdk_library: Allow no_dist to be explicitly set in .bp file

Currently, the no_dist property cannot be set in a .bp file and
defaults to true if the sdk_version property is set to none. That
behavior was added to prevent the output files from the libcore,
conscrypt and icu java_sdk_library modules from being copied to the
dist. It worked because they were the only java_sdk_library modules to
set "sdk_version: none".

Unfortunately, that default behavior is no longer required because
we want to be able to convert "conscrypt" module to a java_sdk_library
and have its public API output files be copied to the dist
automatically. This change allows the no_dist property to be explicitly
set in the .bp file so that those modules that rely on the implicit
behavior can explicitly specify it and allow the default behavior to
be removed.

This change:
* Removes the `blueprint:"mutated"` tag from the No_dist property which
  allows it to be specified in a .bp file.
* Only sets the default if the property has not been explicitly
  specified in a .bp file.

Test: lunch sdk-eng && m dist sdk
      compare out/dist/apistubs directories before and after this
      change to make sure that they have not changed.
Bug: 173715943
Change-Id: I8a1c97b690ae05bfe71ea72acc0831fa51aca7e9