fix(deps): update dependency no.nordicsemi.kotlin.ble:client-android to v2.0.0-alpha15

Author: renovate[bot]

gradle/nordic.versions.toml

@@ -4,7 +4,7 @@
 # The version catalog can be updated independently of this project after the release of this library.
 
 [versions]
-blek = "2.0.0-alpha12" # Version 2.0 alpha 13+ uses Environment and requires common in 2.9+.
+blek = "2.0.0-alpha15" # Version 2.0 alpha 13+ uses Environment and requires common in 2.9+.
 common = "2.7.0" # Version 2.8+ increases minSdk to 23.
 
 [libraries]