ci: Remove disabled changelog-preview workflow

[oioki]

Summary

• changelog-preview.yml used secrets: inherit when calling the reusable getsentry/craft/.github/workflows/changelog-preview.yml, exposing every repository secret to the called workflow.
• The workflow is disabled_manually on GitHub and unused — removed it entirely instead of fixing its secret handling, consistent with how other getsentry repos are dropping this disabled workflow.

Test plan

• Confirmed via GitHub API that the Changelog Preview workflow state is disabled_manually

Fixes VULN-2260

🤖 Generated with Claude Code

[linear-code]

VULN-2260

[sentry]

📲 Install Builds

Android

🔗 App Name	App ID	Version	Configuration
SDK Size	io.sentry.tests.size	8.51.0 (1)	release

⚙️ sentry-android Build Distribution Settings

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	316.04 ms	366.29 ms	50.25 ms
Size	0 B	0 B	0 B

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
d15471f	369.38 ms	459.08 ms	89.70 ms
bbc35bb	324.88 ms	425.73 ms	100.85 ms
b193867	319.59 ms	403.09 ms	83.50 ms
62b579c	299.75 ms	364.84 ms	65.09 ms
382d6c1	306.85 ms	368.70 ms	61.85 ms
48277cd	320.38 ms	379.90 ms	59.52 ms
5b1a06b	315.40 ms	353.33 ms	37.94 ms
ee747ae	415.92 ms	470.15 ms	54.23 ms
37ec571	366.04 ms	424.28 ms	58.23 ms
462dea2	277.68 ms	359.83 ms	82.15 ms

App size

Revision	Plain	With Sentry	Diff
d15471f	1.58 MiB	2.13 MiB	559.54 KiB
bbc35bb	1.58 MiB	2.12 MiB	553.01 KiB
b193867	1.58 MiB	2.19 MiB	620.00 KiB
62b579c	0 B	0 B	0 B
382d6c1	1.58 MiB	2.29 MiB	719.85 KiB
48277cd	0 B	0 B	0 B
5b1a06b	0 B	0 B	0 B
ee747ae	1.58 MiB	2.10 MiB	530.95 KiB
37ec571	0 B	0 B	0 B
462dea2	0 B	0 B	0 B