Fix slf4j provider configuration (unclebob#1520)

Ensure slf4j logging is not lost but is sent to 'java.util.logging' (using 'slf4j-jdk14'), an explicit other provider can be used via the system property slf4j.provider, see SLF4J Manual.

Fixes unclebob#1520

FitNesseRoot/FitNesse/ReleaseNotes/content.txt

@@ -1,4 +1,5 @@
 !2 Pending Changes
+ * Fix SLF4J logging ([[1522][https://github.com/unclebob/fitnesse/pull/1522]])
 
 !2 20240707
  * Allow usage of JDK > 18 ([[1513][https://github.com/unclebob/fitnesse/pull/1513]]).

build.gradle

@@ -53,7 +53,7 @@ sourceSets {
  main {
  java.srcDir 'src'
  resources.srcDir 'src'
- output.resourcesDir java.classesDirectory 
+ output.resourcesDir java.classesDirectory
  }
  test {
  java.srcDir 'test'
@@ -189,7 +189,10 @@ task standaloneJar(type: Jar) {
  from {
  configurations.runtimeClasspath.collect { zipTree(it) }
  } {
- exclude 'META-INF/**'
+ exclude { FileTreeElement details ->
+ details.relativePath.pathString.startsWith('META-INF/') &&
+ !details.relativePath.pathString.equals('META-INF/services/org.slf4j.spi.SLF4JServiceProvider')
+ }
  }
  from jar.outputs.files.collect {
  zipTree(it)