LS Wizard should validate the configuration options are valid JSON

In a user defined LS settings page, if you put invalid json into one of the configuration fields and apply the changes, IJ will throw an exception:

Error while parsing JSON Initialization Options for the language server 'f8f5f681-d78a-4011-bab1-e583018885e2'

com.google.gson.JsonSyntaxException: java.io.EOFException: End of input at line 3 column 1 path $.provideFormatter
	at com.google.gson.internal.Streams.parse(Streams.java:59)
	at com.google.gson.JsonParser.parseReader(JsonParser.java:102)
	at com.google.gson.JsonParser.parseReader(JsonParser.java:70)
	at com.redhat.devtools.lsp4ij.server.definition.launching.UserDefinedLanguageServerDefinition.getLanguageServerInitializationOptions(UserDefinedLanguageServerDefinition.java:104)
	at com.redhat.devtools.lsp4ij.server.definition.launching.UserDefinedStreamConnectionProvider.getInitializationOptions(UserDefinedStreamConnectionProvider.java:68)
	at com.redhat.devtools.lsp4ij.LanguageServerWrapper.lambda$start$0(LanguageServerWrapper.java:326)
	at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1768)
	at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.exec(CompletableFuture.java:1760)
	at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:373)
	at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1182)
	at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1655)
	at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1622)
	at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:165)
Caused by: java.io.EOFException: End of input at line 3 column 1 path $.provideFormatter
	at com.google.gson.stream.JsonReader.nextNonWhitespace(JsonReader.java:1457)
	at com.google.gson.stream.JsonReader.doPeek(JsonReader.java:491)
	at com.google.gson.stream.JsonReader.hasNext(JsonReader.java:422)
	at com.google.gson.internal.bind.TypeAdapters$28.read(TypeAdapters.java:779)
	at com.google.gson.internal.bind.TypeAdapters$28.read(TypeAdapters.java:725)
	at com.google.gson.internal.Streams.parse(Streams.java:49)
	... 12 more

This should be caught before applying the changes.

Start with UserDefinedLanguageServerDefinition.getLanguageServerInitializationOptions and the user-defined LS settings apply flow; the stack trace shows where invalid JSON currently fails. Trace how configuration fields are applied, then ensure malformed JSON is caught before changes are applied and verify that the exception no longer reaches language-server startup.