Remove version from dockerfile rhel10

[phracek]

Remove 'version' label from Dockerfile.rhel10

Konflux build pipeline needs it.
See https://issues.redhat.com/browse/RHELMISC-17288

[phracek]

[test]

[github-actions]

Testing Farm results

name	compose	arch	status	started (UTC)	time	logs
CentOS Stream 10 - 3.12	CentOS-Stream-10	x86_64	✅ passed	12.09.2025 09:50:46	19min 22s	test pipeline
CentOS Stream 9 - 3.9-minimal	CentOS-Stream-9	x86_64	✅ passed	12.09.2025 09:55:02	18min 18s	test pipeline
Fedora - 3.13	Fedora-latest	x86_64	✅ passed	12.09.2025 09:59:14	19min 28s	test pipeline
Fedora - 3.12-minimal	Fedora-latest	x86_64	✅ passed	12.09.2025 10:23:20	17min 24s	test pipeline
RHEL8 - 3.9	RHEL-8.10.0-Nightly	x86_64	✅ passed	12.09.2025 10:33:22	30min 52s	test pipeline
CentOS Stream 10 - 3.12-minimal	CentOS-Stream-10	x86_64	✅ passed	12.09.2025 10:15:24	18min 13s	test pipeline
CentOS Stream 9 - 3.12	CentOS-Stream-9	x86_64	✅ passed	12.09.2025 10:35:51	22min 8s	test pipeline
RHEL9 - 3.9	RHEL-9.6.0-Nightly	x86_64	✅ passed	12.09.2025 10:38:16	31min 11s	test pipeline
CentOS Stream 9 - 3.9	CentOS-Stream-9	x86_64	✅ passed	12.09.2025 09:56:59	20min 4s	test pipeline
CentOS Stream 9 - 3.11-minimal	CentOS-Stream-9	x86_64	✅ passed	12.09.2025 09:59:42	18min 27s	test pipeline
RHEL9 - 3.12-minimal	RHEL-9.6.0-Nightly	x86_64	✅ passed	12.09.2025 10:32:59	29min 22s	test pipeline
Fedora - 3.12	Fedora-latest	x86_64	✅ passed	12.09.2025 09:58:30	20min 26s	test pipeline
RHEL8 - 3.12	RHEL-8.10.0-Nightly	x86_64	✅ passed	12.09.2025 10:23:22	28min 14s	test pipeline
CentOS Stream 9 - 3.12-minimal	CentOS-Stream-9	x86_64	✅ passed	12.09.2025 10:23:23	19min 38s	test pipeline
CentOS Stream 9 - 3.11	CentOS-Stream-9	x86_64	✅ passed	12.09.2025 10:23:05	21min 43s	test pipeline
RHEL10 - 3.12-minimal	RHEL-10-Nightly	x86_64	✅ passed	12.09.2025 09:52:48	21min 29s	test pipeline
RHEL8 - 3.11-minimal	RHEL-8.10.0-Nightly	x86_64	✅ passed	12.09.2025 10:22:33	24min 21s	test pipeline
RHEL8 - 3.9-minimal	RHEL-8.10.0-Nightly	x86_64	✅ passed	12.09.2025 09:53:53	24min 54s	test pipeline
RHEL8 - 3.11	RHEL-8.10.0-Nightly	x86_64	✅ passed	12.09.2025 10:27:48	29min 14s	test pipeline
RHEL9 - 3.12	RHEL-9.6.0-Nightly	x86_64	✅ passed	12.09.2025 10:32:32	32min 51s	test pipeline
RHEL9 - 3.11	RHEL-9.6.0-Nightly	x86_64	✅ passed	12.09.2025 09:50:39	32min 4s	test pipeline

[ljavorsk]

LGTM

[frenzymadness]

I've found one possible improvement in the template logic.

But let me open a broader discussion: What do we need the version label and version ENV variable for? I look at the history, and these versions are the same for many years now without any single change and they are just copy-pasted over and over.

@pkubatrh I saw your comment that we should keep the ENV version so you might know why we need it.

[pkubatrh]

Version label - used to version the image. Historically required by the build system and used as part of the builds NVR. Usually set to 1 in case we ever need to break image compatibility we could increment this version and not break existing deployments. However this was never used (to my knowledge) and current build system ignores it, which is why we can remove it in RHEL10.
VERSION environment variable - Can be used in a variety ways (since it is accessible inside the image). Required for Fedora images so it might accidentally spill into other images as well due to copy-paste errors. Why keep it? Depends on the image really. It might be used inside the image, it might be used by its users in some way, or it might not be used at all.
But since these PRs are only about removing the label, we should focus on that.

[frenzymadness]

Thanks for the context @pkubatrh ! Let's finish this PR, and I'll open a new one where I try to remove them both together with the associated logic, and we'll see what happens.

[phracek]

[test]