workflows and fbtenv improovements (#1661)

* add --restore option, improove clearing
* fix trap
* fix unset
* fix fbtenv clearing
* disabling pvs studio and amap analyses in forks, fbtenv.sh fixes
* fbtenv fix

Co-authored-by: あく <alleteam@gmail.com>

.github/workflows/amap_analyse.yml

@@ -14,6 +14,7 @@ env:
 
 jobs:
   amap_analyse:
+    if: ${{ !github.event.pull_request.head.repo.fork }}
     runs-on: [self-hosted,FlipperZeroMacShell]
     timeout-minutes: 15
     steps:

.github/workflows/pvs_studio.yml

@@ -15,6 +15,7 @@ env:
 
 jobs:
   analyse_c_cpp:
+    if: ${{ !github.event.pull_request.head.repo.fork }}
     runs-on: [self-hosted, FlipperZeroShell]
     steps:
       - name: 'Decontaminate previous build leftovers'