Remove duplicate libraries

[zpin]

The current method of replacing "org.quiltmc:hashed" with "net.fabricmc:intermediary" will result in duplicate entries for "net.fabricmc:intermediary" if the JSON already contains such an entry.
These libraries then get downloaded in parallel, resulting in an "AccessDeniedException" (tested on Windows Server 2019) because the two processes will attempt to write to the same file simultaneously:

Downloading library at: https://maven.fabricmc.net/net/fabricmc/intermediary/1.20.1/intermediary-1.20.1.jar
Downloading library at: https://maven.fabricmc.net/net/fabricmc/intermediary/1.20.1/intermediary-1.20.1.jar
java.util.concurrent.CompletionException: java.io.UncheckedIOException: java.nio.file.AccessDeniedException: .\libraries\net\fabricmc\intermediary\1.20.1\intermediary-1.20.1.jar
        at java.base/java.util.concurrent.CompletableFuture.encodeThrowable(Unknown Source)
        at java.base/java.util.concurrent.CompletableFuture.completeThrowable(Unknown Source)
        at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(Unknown Source)
        at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.exec(Unknown Source)
        at java.base/java.util.concurrent.ForkJoinTask.doExec(Unknown Source)
        at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(Unknown Source)
        at java.base/java.util.concurrent.ForkJoinPool.scan(Unknown Source)
        at java.base/java.util.concurrent.ForkJoinPool.runWorker(Unknown Source)
        at java.base/java.util.concurrent.ForkJoinWorkerThread.run(Unknown Source)
Caused by: java.io.UncheckedIOException: java.nio.file.AccessDeniedException: .\libraries\net\fabricmc\intermediary\1.20.1\intermediary-1.20.1.jar
        at org.quiltmc.installer.action.InstallServer.lambda$downloadLibrary$8(InstallServer.java:272)
        ... 7 more
Caused by: java.nio.file.AccessDeniedException: .\libraries\net\fabricmc\intermediary\1.20.1\intermediary-1.20.1.jar
        at java.base/sun.nio.fs.WindowsException.translateToIOException(Unknown Source)
        at java.base/sun.nio.fs.WindowsException.rethrowAsIOException(Unknown Source)
        at java.base/sun.nio.fs.WindowsException.rethrowAsIOException(Unknown Source)
        at java.base/sun.nio.fs.WindowsFileSystemProvider.newByteChannel(Unknown Source)
        at java.base/java.nio.file.spi.FileSystemProvider.newOutputStream(Unknown Source)
        at java.base/java.nio.file.Files.newOutputStream(Unknown Source)
        at java.base/java.nio.file.Files.copy(Unknown Source)
        at org.quiltmc.installer.action.InstallServer.lambda$downloadLibrary$8(InstallServer.java:267)
        ... 7 more

The suggested change removes duplicate entries from the library list, which solves the issue on my test system.

[TheGlitch76]

Thanks for the PR! There's actually a bit of history behind this hack, and there's a better fix for your issue:
When this hack was written, Quilt Meta ONLY provided Hashed, not Intermediary. Since then, Quilt Meta provides both Hashed and Intermediary, but Quilt Loader versions below 0.17.7 will crash if Hashed is present.

For now, the best solution would be to remove this hack entirely, and I can come in later and add a different hack to remove Hashed entirely if the selected loader version is below 0.17.7 (which will require semver parsing and much more work)

[zpin]

Thank you for the quick reply! That does sound better, yeah.
I'd suggest incorporating this change until the version-specific workaround is in place. This way, it will work for all versions in the meantime.