efi: skip check-alignment-* tests if pefile is not installed

Otherwise, when building with ukify disabled, no one else requires pefile, and
if it is not installed, those tests fail:

```
================================== 12/1212 ===================================
test:         systemd:efi / check-alignment-systemd-bootx64.efi
start time:   14:21:54
duration:     0.08s
result:       exit status 1
command:      /mnt/work/systemd/upstream-fork/main/tools/check-efi-alignment.py /mnt/work/systemd/upstream-fork/main/build/src/boot/efi/systemd-bootx64.efi
----------------------------------- stderr -----------------------------------
Traceback (most recent call last):
  File "/mnt/work/systemd/upstream-fork/main/tools/check-efi-alignment.py", line 7, in <module>
    import pefile
ModuleNotFoundError: No module named 'pefile'
==============================================================================

================================== 13/1212 ===================================
test:         systemd:efi / check-alignment-linuxx64.efi.stub
start time:   14:21:54
duration:     0.08s
result:       exit status 1
command:      /mnt/work/systemd/upstream-fork/main/tools/check-efi-alignment.py /mnt/work/systemd/upstream-fork/main/build/src/boot/efi/linuxx64.efi.stub
----------------------------------- stderr -----------------------------------
Traceback (most recent call last):
  File "/mnt/work/systemd/upstream-fork/main/tools/check-efi-alignment.py", line 7, in <module>
    import pefile
ModuleNotFoundError: No module named 'pefile'
==============================================================================

================================== 14/1212 ===================================
test:         systemd:efi / check-alignment-addonx64.efi.stub
start time:   14:21:54
duration:     0.07s
result:       exit status 1
command:      /mnt/work/systemd/upstream-fork/main/tools/check-efi-alignment.py /mnt/work/systemd/upstream-fork/main/build/src/boot/efi/addonx64.efi.stub
----------------------------------- stderr -----------------------------------
Traceback (most recent call last):
  File "/mnt/work/systemd/upstream-fork/main/tools/check-efi-alignment.py", line 7, in <module>
    import pefile
ModuleNotFoundError: No module named 'pefile'
==============================================================================
```

Follow-up for 7ff3b88

(cherry picked from commit f0896ca)

Related: RHEL-30372

tools/check-efi-alignment.py

@@ -4,7 +4,11 @@
 
 import sys
 
-import pefile
+try:
+    import pefile
+except ImportError as e:
+    print(str(e), file=sys.stderr)
+    sys.exit(77)
 
 
 def main():