Remove unused commons-lang dependency

[merlimat]

Motivation

commons-lang is an unused depenency (already replaced with commons-lang3 in the codebase) that is still getting included as a dependency for BK.

There is a CVE open in common-lang 2.6:

│ commons-lang:commons-lang                                   │ CVE-2025-48924 │ MEDIUM   │          │ 2.6               │                            │ commons-lang/commons-lang: org.apache.commons/commons-lang3: │
│ (commons-lang-commons-lang-2.6.jar)                         │                │          │          │                   │                            │ Uncontrolled Recursion vulnerability in Apache Commons Lang  │
│                                                             │                │          │          │                   │                            │ https://avd.aquasec.com/nvd/cve-2025-48924                   │

Changes

(Describe: what changes you have made)

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