GHA: disable RISC-V for linux-glibc-debian-testing-llvm and linux-glibc-debian-trixie-llvm

```
[2/2] : && /usr/bin/clang-19 --target=riscv64-pc-linux-gnu -Wno-unused-command-line-argument  -fstrict-flex-arrays=3 -fstack-protector-all -fno-omit-frame-pointer -fvisibility=hidden -fno-semantic-interposition -fno-unwind-tables -fno-asynchronous-unwind-tables -ffunction-sections -fdata-sections -isystem /usr/riscv64-linux-gnu/include  -D_FORTIFY_SOURCE=2  -Wl,-z,relro,-z,now -Wl,-z,noexecstack -Wl,-z,nodlopen -Wl,-Bsymbolic -Wl,--gc-sections -Wl,--icf=all -L/usr/riscv64-linux-gnu/lib -L/usr/lib/gcc-cross/riscv64-linux-gnu/14 -fuse-ld=lld-19 -Wl,-s -Wl,--build-id=none  CMakeFiles/cmTC_f18da.dir/testCCompiler.c.o -o cmTC_f18da   && :
FAILED: cmTC_f18da
: && /usr/bin/clang-19 --target=riscv64-pc-linux-gnu -Wno-unused-command-line-argument  -fstrict-flex-arrays=3 -fstack-protector-all -fno-omit-frame-pointer -fvisibility=hidden -fno-semantic-interposition -fno-unwind-tables -fno-asynchronous-unwind-tables -ffunction-sections -fdata-sections -isystem /usr/riscv64-linux-gnu/include  -D_FORTIFY_SOURCE=2  -Wl,-z,relro,-z,now -Wl,-z,noexecstack -Wl,-z,nodlopen -Wl,-Bsymbolic -Wl,--gc-sections -Wl,--icf=all -L/usr/riscv64-linux-gnu/lib -L/usr/lib/gcc-cross/riscv64-linux-gnu/14 -fuse-ld=lld-19 -Wl,-s -Wl,--build-id=none  CMakeFiles/cmTC_f18da.dir/testCCompiler.c.o -o cmTC_f18da   && :
ld.lld-19: error: cannot open Scrt1.o: No such file or directory
ld.lld-19: error: cannot open crti.o: No such file or directory
ld.lld-19: error: cannot open crtbeginS.o: No such file or directory
ld.lld-19: error: cannot open crtendS.o: No such file or directory
ld.lld-19: error: cannot open crtn.o: No such file or directory
clang-19: error: linker command failed with exit code 1 (use -v to see invocation)
ninja: build stopped: subcommand failed.
```
https://github.com/curl/curl-for-win/actions/runs/17629887288/job/50095067795#step:3:3240

Author: vszakats

.github/workflows/build.yml

@@ -106,7 +106,7 @@ jobs:
           COSIGN_PKG_GPG_PASS: '${{ secrets.COSIGN_PKG_GPG_PASS }}'
           COSIGN_PKG_KEY_PASS: '${{ secrets.COSIGN_PKG_KEY_PASS }}'
         run: |
-          export CW_CONFIG="${GITHUB_REF_NAME}-werror-linux"
+          export CW_CONFIG="${GITHUB_REF_NAME}-werror-linux-a64-x64"
           export CW_REVISION="${GITHUB_SHA}"
           . ./_versions.sh
           sudo podman image trust set --type reject default
@@ -181,7 +181,7 @@ jobs:
           COSIGN_PKG_GPG_PASS: '${{ secrets.COSIGN_PKG_GPG_PASS }}'
           COSIGN_PKG_KEY_PASS: '${{ secrets.COSIGN_PKG_KEY_PASS }}'
         run: |
-          export CW_CONFIG="${GITHUB_REF_NAME}-werror-linux"
+          export CW_CONFIG="${GITHUB_REF_NAME}-werror-linux-a64-x64"
           export CW_REVISION="${GITHUB_SHA}"
           DOCKER_IMAGE='debian:trixie-slim'
           sudo podman image trust set --type reject default