fix: Order versioned docs select items by recency (#14768)

## DESCRIBE YOUR PR

This PR makes a change to the order in which we show the version select
items if a docs page has multiple versions: Instead of sorting the
version designator alphabetically, this PR attempts to sort them by
recent to oldest. For now, this only looks at the major number, since
the version designator can be arbitrary and we can't assume proper
semver (see example).If we can't extract a proper major version, we
continue to sort alphabetically.

Before:
<img width="287" height="237" alt="image"
src="https://github.com/user-attachments/assets/d0e39874-3548-4b82-b940-9b4ebdad9a44"
/>

After:
<img width="291" height="240" alt="image"
src="https://github.com/user-attachments/assets/e4f005ad-0f97-4107-8f0c-982f81c8af0e"
/>

(the 10x version in this screenshot serves an illustrative purpose. I'm
not shipping that anytime soon :D)
 
(This PR is brought to you by a sidequest while working on updating
sveltekit docs and encountering weird ordering. Happy to close/adjust as
reviewers see fit :) )

## IS YOUR CHANGE URGENT?  

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to go live.
- [ ] Urgent deadline (GA date, etc.): <!-- ENTER DATE HERE -->
- [ ] Other deadline: Some time week ending Sept 5th
- [x] None: Not urgent, can wait up to 1 week+

## SLA

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- Please give the docs team up to 1 week to review your PR unless you've
added an urgent due date to it.
Thanks in advance for your help!

## PRE-MERGE CHECKLIST

*Make sure you've checked the following before merging your changes:*

- [x] Checked Vercel preview for correctness, including links
- [ ] PR was reviewed and approved by any necessary SMEs (subject matter
experts)
- [ ] PR was reviewed and approved by a member of the [Sentry docs
team](https://github.com/orgs/getsentry/teams/docs)

Author: Lms24

src/components/versionSelector/index.tsx

@@ -11,8 +11,31 @@ import styles from './style.module.scss';
 
 import {VersionBanner} from '../versionBanner';
 
+function sortVersions(versions: string[]) {
+  return versions.sort((a, b) => {
+    const aMajor = parseInt(a.split('.')[0], 10);
+    const bMajor = parseInt(b.split('.')[0], 10);
+
+    if (isNaN(aMajor) || isNaN(bMajor)) {
+      return a.localeCompare(b);
+    }
+
+    if (aMajor < bMajor) {
+      return 1;
+    }
+
+    if (aMajor === bMajor) {
+      // yes, this is flawed. But for now there's no case where we need to order
+      // by minor or patch so I wanna avoid pulling in semver as a dependency
+      return a.localeCompare(b);
+    }
+
+    return -1;
+  });
+}
+
 export function VersionSelector({versions, sdk}: {sdk: string; versions: string[]}) {
-  const availableVersions = ['latest', ...versions];
+  const availableVersions = ['latest', ...sortVersions([...versions])];
   const router = useRouter();
   const pathname = usePathname();