[jdk21u] RFR: 8309032: jpackage does not work for module projects unless --module-path is specified

[airsquared]

Fixes an error when trying to add additional launchers in jpackage.

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Commit messages:
 - Update LauncherData.java
 - Update LauncherData.java

Changes: https://git.openjdk.org/jdk21u/pull/120/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk21u&pr=120&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8309032
  Stats: 16 lines in 1 file changed: 0 ins; 8 del; 8 mod
  Patch: https://git.openjdk.org/jdk21u/pull/120.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u.git pull/120/head:pull/120

PR: https://git.openjdk.org/jdk21u/pull/120