Aliased import may throw java.lang.IllegalArgumentException if nullable and not nullable variants of it are used

[mcarleio]

Describe the bug
An aliased import added via addAliasedImport results in exception java.lang.IllegalArgumentException: Collection has more than one element if the type is used as nullable and as non-nullable.

To Reproduce

package org.example

import com.squareup.kotlinpoet.FileSpec
import com.squareup.kotlinpoet.FunSpec
import com.squareup.kotlinpoet.asTypeName

class PersonId

fun main() {
    println(
        FileSpec.builder("org.example", "SomeFile")
            .addAliasedImport(PersonId::class, "PID")
            .addFunction(
                FunSpec.builder("pid")
                    .returns(PersonId::class.asTypeName().copy(nullable = true))
                    .addCode("return %T()", PersonId::class)
                    .build()
            )
            .build()
    )
}

Expected behavior

package org.example

import org.example.PersonId as PID

public fun pid(): PID? = PID()

Actual behavior

Exception in thread "main" java.lang.IllegalArgumentException: Collection has more than one element.
	at kotlin.collections.CollectionsKt___CollectionsKt.single(_Collections.kt:605)
	at com.squareup.kotlinpoet.CodeWriter$Companion.withCollectedImports(CodeWriter.kt:740)
	at com.squareup.kotlinpoet.FileSpec.writeTo(FileSpec.kt:84)
	at com.squareup.kotlinpoet.FileSpec.toString(FileSpec.kt:222)
	at java.base/java.lang.String.valueOf(String.java:4465)
	at java.base/java.io.PrintStream.println(PrintStream.java:1187)
	at org.example.ExampleKt.main(Example.kt:10)
	at org.example.ExampleKt.main(Example.kt)

Additional context
When you change .addCode("return %T()", PersonId::class) to .addCode("return null") it works.
When you then add .addParameter("pid", PersonId::class), it breaks again.

Used version 2.0.0 above.
Worked with version 1.16.0.
Broken since 1.17.0.

Could be related to #2020