fix: update inspektor gadget v0.51.0 compatibility

[burak-ok]

What this PR does / why we need it:

• Update Inspektor Gadget to v0.51.0
• Stop treating ig and ig-gadgets revision suffixes as a compatibility requirement for every OS

Which issue(s) this PR fixes:

Supersedes #8045 (ig-gadgets v0.51.1 is not available yet)

[Copilot]

Pull request overview

This PR updates the VHD build inputs/tests to support Inspektor Gadget v0.51.0 while relaxing the ig ↔ ig-gadgets compatibility check to require only matching upstream X.Y.Z versions (allowing distro/package revision skew).

Changes:

• Bump inspektor-gadget (ig) versions in parts/common/components.json to 0.51.0 across Ubuntu and Azure Linux.
• Update VHD content tests to validate ig/ig-gadgets compatibility by upstream version (not full distro revision).
• Update VHD build install logic to enforce upstream-version compatibility between ig and the pinned ig-gadgets version, and add ShellSpec coverage for the helper functions.

Package Update Analysis: inspektor-gadget (ig)

Version change: 0.49.1-* → 0.51.0-* (minor update)
OS variants affected: Ubuntu 20.04, Ubuntu 22.04, Ubuntu 24.04, Azure Linux 3.0
OS variants NOT updated: None — full coverage (for the variants listed under inspektor-gadget in components.json)

Upstream changelog not found for this version range in-repo. Manual testing recommended before merge (at minimum: VHD build install path + ig-import-gadgets.service enablement + gadget import tracking file validation).

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
vhdbuilder/packer/test/linux-vhd-content-test.sh	Adds helpers to normalize IG versions and updates the IG asset test to compare upstream X.Y.Z.
vhdbuilder/packer/install-ig.sh	Updates pinned ig-gadgets versions and enforces upstream-version compatibility during VHD build installation.
spec/vhdbuilder/packer/test/linux_vhd_content_test_helpers_spec.sh	Adds ShellSpec tests for the new IG version parsing/comparison helpers.
parts/common/components.json	Bumps ig versions for Ubuntu and Azure Linux to 0.51.0 with updated revision suffixes.

[Copilot]

In ig_extract_upstream_version, the parse-failure message is echoed to stdout. Because callers capture this function via command substitution (e.g., ig_upstream=$(ig_extract_upstream_version ...)), the error text is swallowed into the variable and never reaches logs, making failures hard to diagnose. Please send the error message to stderr (or log from the caller) before returning non-zero.

Suggested change

	echo "[ig] Could not parse upstream version from '${version}'"
	echo "[ig] Could not parse upstream version from '${version}'" >&2

[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

[Copilot]

The version-mismatch error message is echoed to stdout. Since this is an error path (and the function returns non-zero), it should write to stderr (e.g., redirect echo to >&2) so failures are reliably surfaced/grep-able in build logs.

Suggested change

	echo "[ig] ig (${IG_VERSION}) and ig-gadgets (${ig_gadgets_version}) must share upstream version, found ${ig_upstream} vs ${ig_gadgets_upstream}"
	echo "[ig] ig (${IG_VERSION}) and ig-gadgets (${ig_gadgets_version}) must share upstream version, found ${ig_upstream} vs ${ig_gadgets_upstream}" >&2