format checksum to hex

[abe-winter]

What changed

• log hex instead of stringified bytes

Why

Stringified bytes causes the proto library to print 'unable to construct structpb.Struct from map' which distracted me while debugging something else

Sample output

Before:

2025-11-25T21:36:55.156Z WARN viam-agent agent/version_control.go:263 mismatched checksum, redownloading {"expected":"\ufffdt\ufffd~\ufffd\u0004\ufffd\ufffd\ufffd*\ufffdx0\ufffd<\ufffd\ufffd\ufffd4\ufffd\ufffdz`t+\ufffdؐ0jL\ufffd","actual":"","url":"https://storage.googleapis.com/download/storage/v1/b/packages.viam.com/o/apps%2Fviam-agent%2Fviam-agent-v0.23.0-x86_64?generation=1762893861750149&alt=media"}

unable to construct structpb.Struct from map map[Integer:0 Interface: Key:expected String:�t�~����*�x0�<���4��zt+�ؐ0jL� Type:15]: proto: invalid UTF-8 in string: "\xb6t\x94~\xf4\x04\xb4\x80\xf1*\xcfx0\xdc<\x89\xa7\x844\xbb\xf7zt+\x9dؐ0jL\xef"2025-11-25T21:36:55.156Z INFOviam-agent utils/utils.go:160 Starting download of https://storage.googleapis.com/download/storage/v1/b/packages.viam.com/o/apps%2Fviam-agent%2Fviam-agent-v0.23.0-x86_64?generation=1762893861750149&alt=media

After:

2025-11-25T22:04:20.571Z WARN viam-agent agent/version_control.go:264 mismatched checksum, redownloading {"expected":"b674947ef404b480f12acf7830dc3c89a78434bbf77a60742b9dd890306a4cef","actual":"","url":"https://storage.googleapis.com/download/storage/v1/b/packages.viam.com/o/apps%2Fviam-agent%2Fviam-agent-v0.23.0-x86_64?generation=1762893861750149&alt=media"}

2025-11-25T22:04:20.572Z INFO viam-agent utils/utils.go:160 Starting download of https://storage.googleapis.com/download/storage/v1/b/packages.viam.com/o/apps%2Fviam-agent%2Fviam-agent-v0.23.0-x86_64?generation=1762893861750149&alt=media