Replace kotlin compile testing with a fork

That follows Kotlin updates more frequently. This addresses `incompatible version of Kotlin` error.

Specify `-language-version` to `1.9` as higher version seems to influence which KSP is executed. Inspired by: https://github.com/square/moshi/blob/d88d91d8394f418fd47b182c841b9a3e3a3e0a0b/moshi-kotlin-codegen/src/test/java/com/squareup/moshi/kotlin/codegen/ksp/JsonClassSymbolProcessorTest.kt#L856

gradle/libs.versions.toml

@@ -81,7 +81,7 @@ jna = '5.15.0@aar'
 json-path = '2.9.0'
 jsoup = '1.18.3'
 junit = '4.13.2'
-kotlin-compile-testing = '1.6.0'
+kotlin-compile-testing = '0.7.0'
 kotlin-main = '2.1.0'
 kotlinx-coroutines = '1.8.1'
 kotlinx-kover = '0.7.6'
@@ -232,8 +232,8 @@ jna = { module = "net.java.dev.jna:jna", version.ref = "jna" }
 json-path = { group = "com.jayway.jsonpath", name = "json-path", version.ref = "json-path" }
 jsoup = { group = "org.jsoup", name = "jsoup", version.ref = "jsoup" }
 junit = { group = "junit", name = "junit", version.ref = "junit" }
-kotlin-compile-testing-ksp = { group = "com.github.tschuchortdev", name = "kotlin-compile-testing-ksp", version.ref = "kotlin-compile-testing" }
-kotlin-compile-testing-main = { group = "com.github.tschuchortdev", name = "kotlin-compile-testing", version.ref = "kotlin-compile-testing" }
+kotlin-compile-testing-ksp = { group = "dev.zacsweers.kctfork", name = "ksp", version.ref = "kotlin-compile-testing" }
+kotlin-compile-testing-main = { group = "dev.zacsweers.kctfork", name = "core", version.ref = "kotlin-compile-testing" }
 kotlin-reflect = { group = "org.jetbrains.kotlin", name = "kotlin-reflect", version.ref = "kotlin-main" }
 kotlin-test-junit = { group = "org.jetbrains.kotlin", name = "kotlin-test-junit", version.ref = "kotlin-main" }
 kotlinx-coroutines-android = { group = "org.jetbrains.kotlinx", name = "kotlinx-coroutines-android", version.ref = "kotlinx-coroutines" }

libs/processors/src/test/kotlin/org/wordpress/android/processor/RemoteConfigProcessorTest.kt

@@ -2,8 +2,7 @@ package org.wordpress.android.processor
 
 import com.tschuchort.compiletesting.KotlinCompilation
 import com.tschuchort.compiletesting.SourceFile
-import com.tschuchort.compiletesting.kspWithCompilation
-import com.tschuchort.compiletesting.symbolProcessorProviders
+import com.tschuchort.compiletesting.configureKsp
 import org.assertj.core.api.Assertions.assertThat
 import org.jetbrains.kotlin.compiler.plugin.ExperimentalCompilerApi
 import org.jetbrains.kotlin.utils.addToStdlib.UnsafeCastFunction
@@ -119,10 +118,14 @@ class RemoteConfigProcessorTest {
 
     private fun compile(src: List<SourceFile>) = KotlinCompilation().apply {
         sources = src + fakeAppConfig
-        symbolProcessorProviders = listOf(RemoteConfigProcessorProvider())
-        kspWithCompilation = true
         inheritClassPath = true
+        verbose = true
         messageOutputStream = System.out
+        configureKsp(useKsp2 = false) {
+            symbolProcessorProviders += RemoteConfigProcessorProvider()
+            withCompilation = true
+            languageVersion = "1.9"
+        }
     }.compile()
 
     // Fake AppConfig is needed, as it's a class that is expected to be present in the classpath. Originally, this class