fix: explicitly specify the DB name when migrating

[motorina0]

Summary

Each extension has a DB version stored in the dbversions table. When an extension is upgraded this version can change if there are new scripts in migration.py file.

The bug is on extension upgrade. The temp upgraded module name was used for the dbversions table:

The fix uses the explicit DB name.

Test Steps:

• install an extension with a lower version (eg: satspay v0.2.3)
• upgrade to a higher version (eg: satspay v0.2.5)

Actual Result:

• two entries for satspay are now in the dbversions (see screenshot)

Expected Result:

• the satspay entry gets updated to version 7
• no new satspay entry in dbversions

Note:

• I suspect this bug was introduced with this PR Support custom path for installed extensions #1940

[codecov]

Codecov Report

Merging #2039 (c522554) into dev (e522a53) will decrease coverage by 0.01%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##              dev    #2039      +/-   ##
==========================================
- Coverage   61.73%   61.73%   -0.01%     
==========================================
  Files          55       55              
  Lines        8076     8075       -1     
==========================================
- Hits         4986     4985       -1     
  Misses       3090     3090              

Files	Coverage Δ
lnbits/commands.py	64.28% <100.00%> (ø)
lnbits/core/helpers.py	49.05% <50.00%> (-0.95%)	⬇️

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[jackstar12]

• I suspect this bug was introduced with this PR Support custom path for installed extensions #1940

Just checked, it happened here:
https://github.com/lnbits/lnbits/pull/1940/files#diff-82afd4105ca2e11a7f9683427475878700edea7b4fb0d15321b386970e4a89d0L185-R197

The update module name broke the [-2] index, which was pretty dirty.