Add new v1.14 Firecracker version

[bchalios]

Firecracker team disclosed a vulnerability on the VirtIO PCI implementation [1]. We are not affected since we don't use PCI for our sandboxes, but we might want to enable that in the future, so we rebase our changes on top of the fixes. This commit creates a new build that uses the fixed version.

[1] GHSA-776c-mpj7-jm3r

[cursor]

PR Summary

Low Risk
Single-line update to the Firecracker versions list; low code risk, but it changes which microVM binary build may be selected for v1.14.

Overview
Updates firecracker_versions.txt to replace the listed v1.14.1 build hash (76f16f0 -> 458ca91) for amd64,arm64, effectively switching consumers to the newer v1.14.1 build.

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[dobrac]

This replaces the version. Is that ok - won't it break existing deployments?

[bchalios]

This replaces the version. Is that ok - won't it break existing deployments?

We don't delete prior builds. This only instructs what we should build. Also, we haven't deployed v1.14 yet.