FR: harmonize `GradleException` content between List and Tree

List and Tree modes throw different exception content.

# Tree

```
***** DEPENDENCY CHANGE DETECTED *****
-\--- androidx.activity:activity:1.4.0
- +--- androidx.annotation:annotation:1.1.0 -> 1.2.0
- +--- androidx.core:core:1.7.0
- | +--- androidx.annotation:annotation:1.2.0
- | +--- androidx.annotation:annotation-experimental:1.1.0
- | +--- androidx.lifecycle:lifecycle-runtime:2.3.1
- | | +--- androidx.arch.core:core-runtime:2.1.0
- | | | +--- androidx.annotation:annotation:1.1.0 -> 1.2.0
- | | | \--- androidx.arch.core:core-common:2.1.0
- | | | \--- androidx.annotation:annotation:1.1.0 -> 1.2.0
- | | +--- androidx.lifecycle:lifecycle-common:2.3.1
- | | | \--- androidx.annotation:annotation:1.1.0 -> 1.2.0
- | | +--- androidx.arch.core:core-common:2.1.0 (*)
- | | \--- androidx.annotation:annotation:1.1.0 -> 1.2.0
- | +--- androidx.versionedparcelable:versionedparcelable:1.1.1
- | | +--- androidx.annotation:annotation:1.1.0 -> 1.2.0
- | | \--- androidx.collection:collection:1.0.0
- | | \--- androidx.annotation:annotation:1.0.0 -> 1.2.0
- | +--- androidx.collection:collection:1.0.0 (*)
- | \--- androidx.concurrent:concurrent-futures:1.0.0
- | +--- com.google.guava:listenablefuture:1.0
- | \--- androidx.annotation:annotation:1.1.0 -> 1.2.0
- +--- androidx.lifecycle:lifecycle-runtime:2.3.1 (*)
- +--- androidx.lifecycle:lifecycle-viewmodel:2.3.1
- | \--- androidx.annotation:annotation:1.1.0 -> 1.2.0
- +--- androidx.savedstate:savedstate:1.1.0
- | +--- androidx.annotation:annotation:1.1.0 -> 1.2.0
- | +--- androidx.arch.core:core-common:2.0.1 -> 2.1.0 (*)
- | \--- androidx.lifecycle:lifecycle-common:2.0.0 -> 2.3.1 (*)
- +--- androidx.lifecycle:lifecycle-viewmodel-savedstate:2.3.1
- | +--- androidx.annotation:annotation:1.0.0 -> 1.2.0
- | +--- androidx.savedstate:savedstate:1.1.0 (*)
- | +--- androidx.lifecycle:lifecycle-livedata-core:2.3.1
- | | +--- androidx.arch.core:core-common:2.1.0 (*)
- | | +--- androidx.arch.core:core-runtime:2.1.0 (*)
- | | \--- androidx.lifecycle:lifecycle-common:2.3.1 (*)
- | \--- androidx.lifecycle:lifecycle-viewmodel:2.3.1 (*)
- +--- org.jetbrains.kotlin:kotlin-stdlib:1.5.31 -> 1.6.10 (*)
- +--- androidx.collection:collection:1.0.0 (*)
- \--- androidx.tracing:tracing:1.0.0
- \--- androidx.annotation:annotation:1.1.0 -> 1.2.0
+\--- androidx.activity:activity:1.4.1 FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':sample:app:dependencyTreeDiffReleaseRuntimeClasspath'.
> ***** DEPENDENCY CHANGE DETECTED *****
Dependency Tree comparison to baseline does not match.

If this is intentional, re-baseline using ./gradlew :sample:app:dependencyGuardBaseline
Or use ./gradlew dependencyGuardBaseline to re-baseline dependencies in entire project.

* Try:
> Run with --stacktrace option to get the stack trace.
> Run with --info or --debug option to get more log output.
> Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 9s
9:07:35 pm: Execution finished ':sample:app:dependencyGuard --quiet'.

```

# List

```
Dependencies Changed in :sample:app for configuration releaseRuntimeClasspath
- androidx.activity:activity:1.4.0
- androidx.annotation:annotation-experimental:1.1.0
- androidx.annotation:annotation:1.2.0
- androidx.arch.core:core-common:2.1.0
- androidx.arch.core:core-runtime:2.1.0
- androidx.collection:collection:1.0.0
- androidx.concurrent:concurrent-futures:1.0.0
- androidx.core:core:1.7.0
- androidx.lifecycle:lifecycle-common:2.3.1
- androidx.lifecycle:lifecycle-livedata-core:2.3.1
- androidx.lifecycle:lifecycle-runtime:2.3.1
- androidx.lifecycle:lifecycle-viewmodel-savedstate:2.3.1
- androidx.lifecycle:lifecycle-viewmodel:2.3.1
- androidx.savedstate:savedstate:1.1.0
- androidx.tracing:tracing:1.0.0
- androidx.versionedparcelable:versionedparcelable:1.1.1
- com.google.guava:listenablefuture:1.0

If this is intentional, re-baseline using ./gradlew :sample:app:dependencyGuardBaseline
Or use ./gradlew dependencyGuardBaseline to re-baseline dependencies in entire project.

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':sample:app:dependencyGuard'.
> Dependencies Changed in :sample:app for configuration releaseRuntimeClasspath
- androidx.activity:activity:1.4.0
- androidx.annotation:annotation-experimental:1.1.0
- androidx.annotation:annotation:1.2.0
- androidx.arch.core:core-common:2.1.0
- androidx.arch.core:core-runtime:2.1.0
- androidx.collection:collection:1.0.0
- androidx.concurrent:concurrent-futures:1.0.0
- androidx.core:core:1.7.0
- androidx.lifecycle:lifecycle-common:2.3.1
- androidx.lifecycle:lifecycle-livedata-core:2.3.1
- androidx.lifecycle:lifecycle-runtime:2.3.1
- androidx.lifecycle:lifecycle-viewmodel-savedstate:2.3.1
- androidx.lifecycle:lifecycle-viewmodel:2.3.1
- androidx.savedstate:savedstate:1.1.0
- androidx.tracing:tracing:1.0.0
- androidx.versionedparcelable:versionedparcelable:1.1.1
- com.google.guava:listenablefuture:1.0

If this is intentional, re-baseline using ./gradlew :sample:app:dependencyGuardBaseline
Or use ./gradlew dependencyGuardBaseline to re-baseline dependencies in entire project.

* Try:
> Run with --stacktrace option to get the stack trace.
> Run with --info or --debug option to get more log output.
> Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 2s
```

---

As you can see, the List output contains the diff twice. Moreover, the colored diff output is generally hidden, and only the last bit appear, which is the `GradleException` message. (and the first line is different as well)
Do you think we could harmonize this behavior?

- Tree (ad-hoc message)

https://github.com/dropbox/dependency-guard/blob/56ba80d9612e5de24a1d9e722f9befaf9ef19a47/dependency-guard/src/main/kotlin/com/dropbox/gradle/plugins/dependencyguard/internal/utils/DependencyGuardTreeDiffer.kt#L66-L72

- List (reuses the exception message, leading to duplicated output)

https://github.com/dropbox/dependency-guard/blob/56ba80d9612e5de24a1d9e722f9befaf9ef19a47/dependency-guard/src/main/kotlin/com/dropbox/gradle/plugins/dependencyguard/internal/list/DependencyGuardListTask.kt#L105