RFR: 4870789: RFE: UIDefaults.getUIError() hides real error

[Prasanta Sadhukhan]

`UIDefaults.getUIError` method is invoked when an exception occurred in UI code but this method hides the underlying exception, this method could be more useful if the original exception is passed as argument and used as the cause of the Error thrown from `getUIError` body

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Commit messages:
 - 4870789: RFE: UIDefaults.getUIError() hides real error

Changes: https://git.openjdk.org/jdk/pull/26567/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26567&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-4870789
  Stats: 14 lines in 3 files changed: 1 ins; 0 del; 13 mod
  Patch: https://git.openjdk.org/jdk/pull/26567.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26567/head:pull/26567

PR: https://git.openjdk.org/jdk/pull/26567