fix: update tailscale fork to fix TSMP/ICMP callback leak (backport 2.33) (#25472)

Backport of #25469 to `release/2.33`.

Updates `github.com/coder/tailscale` to
[`v1.1.1-0.20260519043957-6f014ff9434f`](coder/tailscale@6f014ff)
to include the fix from
[coder/tailscale#122](coder/tailscale#122),
which ports the upstream
[tailscale/tailscale#18113](tailscale/tailscale#18113)
fix for TSMP/ICMP callback leaks.

Fixes #25380

> Generated with [Coder Agents](https://coder.com) by @rowansmithau

Author: rowansmithau

go.mod

@@ -36,7 +36,7 @@ replace github.com/tcnksm/go-httpstat => github.com/coder/go-httpstat v0.0.0-202
 
 // There are a few minor changes we make to Tailscale that we're slowly upstreaming. Compare here:
 // https://github.com/tailscale/tailscale/compare/main...coder:tailscale:main
-replace tailscale.com => github.com/coder/tailscale v1.1.1-0.20260409064601-e956a950740b
+replace tailscale.com => github.com/coder/tailscale v1.1.1-0.20260519043957-6f014ff9434f
 
 // This is replaced to include
 // 1. a fix for a data race: c.f. https://github.com/tailscale/wireguard-go/pull/25

go.sum

@@ -348,8 +348,8 @@ github.com/coder/serpent v0.14.0 h1:g7vt2zBMp3nWyAvyhvQduaI53Ku65U3wITMi01+/8pU=
 github.com/coder/serpent v0.14.0/go.mod h1:7OIvFBYMd+OqarMy5einBl8AtRr8LliopVU7pyrwucY=
 github.com/coder/ssh v0.0.0-20231128192721-70855dedb788 h1:YoUSJ19E8AtuUFVYBpXuOD6a/zVP3rcxezNsoDseTUw=
 github.com/coder/ssh v0.0.0-20231128192721-70855dedb788/go.mod h1:aGQbuCLyhRLMzZF067xc84Lh7JDs1FKwCmF1Crl9dxQ=
-github.com/coder/tailscale v1.1.1-0.20260409064601-e956a950740b h1:HW3db+iEczHHSsPLJokZRJTO788qf782qJcR9YAeAaM=
-github.com/coder/tailscale v1.1.1-0.20260409064601-e956a950740b/go.mod h1:9lK5yqqKpK5yhDv4G8ZDDHr2S8EATEjLyUkLTKDbPzU=
+github.com/coder/tailscale v1.1.1-0.20260519043957-6f014ff9434f h1:gYivllu5CHhvRr4SM93zSQDj9cG2V+Pc0URTFy3fF/Y=
+github.com/coder/tailscale v1.1.1-0.20260519043957-6f014ff9434f/go.mod h1:WTWP5ZNODDXHwWlQ1Jc2MFhqxu93pUs7lIy28Fd5a5E=
 github.com/coder/terraform-config-inspect v0.0.0-20250107175719-6d06d90c630e h1:JNLPDi2P73laR1oAclY6jWzAbucf70ASAvf5mh2cME0=
 github.com/coder/terraform-config-inspect v0.0.0-20250107175719-6d06d90c630e/go.mod h1:Gz/z9Hbn+4KSp8A2FBtNszfLSdT2Tn/uAKGuVqqWmDI=
 github.com/coder/terraform-provider-coder/v2 v2.16.0 h1:n5/RkxVWuhjQWLqBYkjcUzNIR01JGnpHnqMso6IZBGE=