chore(deps): update plugin com.gradleup.shadow to v9.4.0 (#7034)

This PR contains the following updates:

| Package | Change |
[Age](https://docs.renovatebot.com/merge-confidence/) |
[Confidence](https://docs.renovatebot.com/merge-confidence/) |
|---|---|---|---|
| com.gradleup.shadow | `9.2.2` → `9.4.0` |
![age](https://developer.mend.io/api/mc/badges/age/maven/com.gradleup.shadow:com.gradleup.shadow.gradle.plugin/9.4.0?slim=true)
|
![confidence](https://developer.mend.io/api/mc/badges/confidence/maven/com.gradleup.shadow:com.gradleup.shadow.gradle.plugin/9.2.2/9.4.0?slim=true)
|

---

### Configuration

📅 **Schedule**: Branch creation - Between 12:00 AM and 03:59 AM, only on
Monday ( * 0-3 * * 1 ) (UTC), Automerge - At any time (no schedule
defined).

🚦 **Automerge**: Enabled.

♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the
rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update
again.

---

- [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check
this box

---

This PR was generated by [Mend Renovate](https://mend.io/renovate/).
View the [repository job
log](https://developer.mend.io/github/vortex-data/vortex).

<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0My42Ni40IiwidXBkYXRlZEluVmVyIjoiNDMuNjYuNCIsInRhcmdldEJyYW5jaCI6ImRldmVsb3AiLCJsYWJlbHMiOlsiY2hhbmdlbG9nL2Nob3JlIl19-->

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

java/vortex-jni/build.gradle.kts

@@ -8,7 +8,7 @@ plugins {
     `java-library`
     `jvm-test-suite`
     id("com.google.protobuf")
-    id("com.gradleup.shadow") version "9.2.2"
+    id("com.gradleup.shadow") version "9.4.0"
 }
 
 dependencies {

java/vortex-spark/build.gradle.kts

@@ -8,7 +8,7 @@ apply(plugin = "com.vanniktech.maven.publish")
 plugins {
     `java-library`
     `jvm-test-suite`
-    id("com.gradleup.shadow") version "9.2.2"
+    id("com.gradleup.shadow") version "9.4.0"
 }
 
 dependencies {