[BUG] on.exit causing crashes

[smusali]

One of the changes I have included in #21 is to turn off on.exit in extras/CodeToRun*.R because of the following error while running those scripts on MacOS:

Error in `.createErrorReport()`:
! Error executing SQL:
Invalid or closed connection
An error report has been created at  .../Trajectories/errorReportSql.txt

errorReportSql.txt says the following:

DBMS:
sqlite

Error:
Invalid or closed connection

SQL:
SELECT COUNT(*) AS CCC FROM main.cohort WHERE cohort_definition_id = 1;

R version:
R version 4.2.2 (2022-10-31)

Platform:
aarch64-apple-darwin20

Attached base packages:
- stats
- graphics
- grDevices
- utils
- datasets
- methods
- base

Other attached packages:
- stringi (1.7.12)
- Eunomia (1.0.2)
- drat (0.2.3)
- DatabaseConnector (6.0.0)
- Trajectories (1.0.0)
- dplyr (1.1.0)

Turning off on.exit solves the issue because at the end of each script, it quits by disconnecting from the database with the following commands:

DatabaseConnector::disconnect(connection)

We need to safely and gracefully exit by disconnecting in the case of error only but I couldn't find a way to replace on.exit for such cases.