Eliminate fixed-length char arrays in histogram metadata merging

Addresses crash seen in ATR-21126

This merge request affects 1 package:

• DataQuality/DataQualityUtils

added DQ master review-pending-level-1 labels

CI Result SUCCESS (hash eee93fc0)

	Athena	AthSimulation	AnalysisBase
externals
cmake
make
required tests
optional tests

Full details available on this CI monitor view
Athena: number of compilation errors 0, warnings 1
AthSimulation: number of compilation errors 0, warnings 0
AnalysisBase: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 11720]

Make warning is unrelated and fixed by !31660 (merged)

Changes look fine and, as @ponyisi says, the warning is unrelated. Approving. Clara (L1)

added review-approved label and removed review-pending-level-1 label

merged

mentioned in commit 102fc216

added sweep:ignore label