Add ui-backhandler dependency shortcut

[MaximPestryakov]

In 1.8.0 release multiplatform BackHandler and PredictiveBackHandler were implemented. But shortcut for ui-backhandler dependency wasn't. To be able to use
BackHandler you have to manually add org.jetbrains.compose.ui:ui-backhandler dependency.

Now you add the dependency like this:

dependencies {
    implementation(compose.uiBackHandler)
}

[kropp]

We are deprecating dependency aliases in #5462, so I'm closing this PR.
These aliases added unnecessary magic to the users' build files and unnecessary complexity to our builds.

[MatkovIvan]

Also please note that this module was experimental/temopal solution. Now, all APIs there are deprecated (see JetBrains/compose-multiplatform-core#2382), NavigationEventHandler is a replacement