Fix rust installed libraries mode and symlinks (#30129)

- **rust-1.81: mark all installed libraries executable**
  This fixes missing provides for so:librustc_driver..... library

- **rust-1.81: Drop bogus symlinks**
  This paragraph appears to install symlinks for x86_64 & i686.
  
  However, this seems like a Debian-ism multi-arch stuff.
  
Note in our x86_64 builds, no i686 build is performed, thus the command
generated a broken symlink name `*.so` verbantim:
  
  ```
curl -sL
https://apk.cgr.dev/wolfi-presubmit/c30ab744952a5794072e2657bfddc529a54e6c61/x86_64/rust-1.81-1.81.0-r1.apk
| tar -tvz usr/lib32
  d????????? ?/?               0 ????-??-?? ??:?? ..
lrwxrwxrwx 0/0 0 2024-10-06 04:16 *.so ->
../lib/rustlib/i686-unknown-linux-gnu/lib/*.so
  ```
  
  On both x86_64 and arm64 builds.
  
  Lets drop these and observe what happens, and double check if
  rustbuild still installs duplicated files or not.

rust-1.81.yaml

@@ -1,7 +1,7 @@
 package:
  name: rust-1.81
  version: 1.81.0
- epoch: 0
+ epoch: 1
  description: "Empowering everyone to build reliable and efficient software."
  copyright:
  - license: Apache-2.0 AND MIT
@@ -112,13 +112,9 @@ pipeline:
  rm ${{targets.destdir}}/usr/lib/rustlib/uninstall.sh
  rm ${{targets.destdir}}/usr/lib/rustlib/manifest-*
 
- # rustbuild always installs copies of the shared libraries to /usr/lib,
- # overwrite them with symlinks to the per-architecture versions
- - runs: |
- mkdir -p ${{targets.destdir}}/usr/lib32
- cd ${{targets.destdir}}
- ln -srft usr/lib usr/lib/rustlib/x86_64-unknown-linux-gnu/lib/*.so
- ln -srft usr/lib32 usr/lib/rustlib/i686-unknown-linux-gnu/lib/*.so
+ - name: ensure libraries are executable for melange SCA provides generation
+ runs: |
+ chmod +x ${{targets.destdir}}/usr/lib/*.so
 
 update:
  enabled: true