Scripts passed with the -script switch conflict with script folders

Steps:

1. Launch ZAP GUI
2. Add script folder in the list of script folders (options -> scripts -> add folder), i.e.: c:\zapscripts
3. Create standalone zest script "justinbieber.zst" and store it in "c:\zapscripts\standalone\justinbieber.zst"
4. Close ZAP GUI

Observed:
Path A) Execute: zap.bat -cmd -script c:\zapscripts\standalone\justinbieber.zst
ZAP returns silently.
Path B) Execute: zap.bat -script c:\zapscripts\standalone\justinbieber.zst
An exception is thrown in the console:
6915 [ZAP-BootstrapGUI] ERROR org.zaproxy.zap.extension.script.ExtensionScript - A script with the same name already exists: justinbieber.zst
java.security.InvalidParameterException: A script with the same name already exists: justinbieber.zst
at org.zaproxy.zap.extension.script.ScriptTreeModel.addScript(Unknown Source)
at org.zaproxy.zap.extension.script.ExtensionScript.addScript(Unknown Source)
at org.zaproxy.zap.extension.script.ExtensionScript.addScript(Unknown Source)
at org.zaproxy.zap.extension.script.ExtensionScript.openCmdLineFile(Unknown Source)
at org.zaproxy.zap.extension.script.ExtensionScript.execute(Unknown Source)
at org.parosproxy.paros.extension.ExtensionLoader.runCommandLine(Unknown Source)
at org.parosproxy.paros.control.Control.runCommandLine(Unknown Source)
at org.zaproxy.zap.GuiBootstrap.initControlAndPostViewInit(Unknown Source)
at org.zaproxy.zap.GuiBootstrap.access$100(Unknown Source)
at org.zaproxy.zap.GuiBootstrap$2.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

Expected:
When a script is launched by an explicit call to the -script switch in the command line, it may show a clear intent from the user ("I want to execute this script"), therefore scripts marked for automated loading at start (i.e. no execution) should either be ignored/skipped or at least not trigger a conflict and result in a silent "ignore".

Start at ExtensionScript.openCmdLineFile and the ScriptTreeModel.addScript call shown in the stack trace, then reproduce both zap.bat command-line paths with a script folder containing the same Zest script. Done means an explicit -script invocation does not raise the duplicate-name conflict when the script is already loaded or marked for automated loading, and the behavior is verified for the reported setup.