fix(aws): Launch template version of ASG default to '$Latest' when not defined (backport #6373)

[mergify]

An edge case involves an ASG created via CloudFormation or via a Crossplane custom resource which the launchTemplate.version not defined. According to the AWS docs this defaults to $Latest as it is not a mandatory field.

When Clouddriver caches it and if it matches an Application name it will be present in the Cluster view tab. This causes an NPE on the ServerGroupController as:

2025-05-15 09:55:00.341 ERROR 1 — [0.0-7002-exec-8] c.n.s.k.w.e.GenericExceptionHandlers     : Internal Server Error
java.lang.NullPointerException: Cannot invoke method toInteger() on null object
at org.codehaus.groovy.runtime.NullObject.invokeMethod(NullObject.java:98) ~[groovy-4.0.15.jar:4.0.15]
at org.codehaus.groovy.vmplugin.v8.IndyGuardsFiltersAndSignatures.invokeGroovyObjectInvoker(IndyGuardsFiltersAndSignatures.java:151) ~[groovy-4.0.15.jar:4.0.15]
at org.codehaus.groovy.vmplugin.v8.IndyInterface.fromCache(IndyInterface.java:321) ~[groovy-4.0.15.jar:4.0.15]
at com.netflix.spinnaker.clouddriver.aws.provider.view.AmazonClusterProvider$_getLaunchTemplateForVersion_closure27.doCall(AmazonClusterProvider.groovy:549) ~[clouddriver-aws-2025.04.10.18.48.11.release-1.36.x.jar:2025.04.10.18.48.11.release-1.36.x]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
at java.base/java.lang.reflect.Method.invoke(Method.java:569) ~[na:na]
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:343) ~[groovy-4.0.15.jar:4.0.15]
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:328) ~[groovy-4.0.15.jar:4.0.15]
at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:279) ~[groovy-4.0.15.jar:4.0.15]
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1008) ~[groovy-4.0.15.jar:4.0.15]
at org.codehaus.groovy.runtime.callsite.PogoMetaClassSite.call(PogoMetaClassSite.java:39) ~[groovy-4.0.15.jar:4.0.15]
at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:45) ~[groovy-4.0.15.jar:4.0.15]
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:125) ~[groovy-4.0.15.jar:4.0.15]
at org.codehaus.groovy.runtime.callsite.BooleanReturningMethodInvoker.invoke(BooleanReturningMethodInvoker.java:49) ~[groovy-4.0.15.jar:4.0.15]
at org.codehaus.groovy.runtime.callsite.BooleanClosureWrapper.call(BooleanClosureWrapper.java:52) ~[groovy-4.0.15.jar:4.0.15]
at org.codehaus.groovy.runtime.DefaultGroovyMethods.find(DefaultGroovyMethods.java:4357) ~[groovy-4.0.15.jar:4.0.15]
at org.codehaus.groovy.runtime.dgm$242.doMethodInvoke(Unknown Source) ~[groovy-4.0.15.jar:4.0.15]
at org.codehaus.groovy.vmplugin.v8.IndyInterface.fromCache(IndyInterface.java:321) ~[groovy-4.0.15.jar:4.0.15]
at com.netflix.spinnaker.clouddriver.aws.provider.view.AmazonClusterProvider.getLaunchTemplateForVersion(AmazonClusterProvider.groovy:548) ~[clouddriver-aws-2025.04.10.18.48.11.release-1.36.x.jar:2025.04.10.18.48.11.release-1.36.x]
at org.codehaus.groovy.vmplugin.v8.IndyInterface.fromCache(IndyInterface.java:321) ~[groovy-4.0.15.jar:4.0.15]
at com.netflix.spinnaker.clouddriver.aws.provider.view.AmazonClusterProvider.populateServerGroupWithLtOrMip(AmazonClusterProvider.groovy:582) ~[clouddriver-aws-2025.04.10.18.48.11.release-1.36.x.jar:2025.04.10.18.48.11.release-1.36.x]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
at java.base/java.lang.reflect.Method.invoke(Method.java:569) ~[na:na]
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:343) ~[groovy-4.0.15.jar:4.0.15]
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:328) ~[groovy-4.0.15.jar:4.0.15]
at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:342) ~[groovy-4.0.15.jar:4.0.15]
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1008) ~[groovy-4.0.15.jar:4.0.15]
at org.codehaus.groovy.vmplugin.v8.IndyInterface.fromCache(IndyInterface.java:321) ~[groovy-4.0.15.jar:4.0.15]
at com.netflix.spinnaker.clouddriver.aws.provider.view.AmazonClusterProvider$_updateServerGroupLaunchSettings_closure28.doCall(AmazonClusterProvider.groovy:564) ~[clouddriver-aws-2025.04.10.18.48.11.release-1.36.x.jar:2025.04.10.18.48.11.release-1.36.x]
...

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This is an automatic backport of pull request #6373 done by [Mergify](https://mergify.com).