ci: peg ubuntu image

[detule]

This is likely temporary, but would allow business as usual while we resolve some of the issues with the new runner image.

• First note the announcement here.
• Some issues I see in the "DB" pipeline with the new image - will tackle subsequently:

1. MySQL driver installation fails. This could be due to a newer cmake or the newer driver manager.

 CMake Error at CMakeLists.txt:263 (MESSAGE):
  Driver Manager was not found

2. SQL Server tests fail with

ODBC failed with error 00000 from [Microsoft][ODBC Driver 17 for SQL Server][OpenSSL library could not be loaded, make sure OpenSSL 1.0 or 1.1 is installed]

3. Oracle tests fail with

[unixODBC][Driver Manager]Can't open lib '/opt/oracle/instantclient_21_12/libsqora.so.21.1' : file not found ")

( though as best as I can tell, the driver is actually installed ).

For reference, something similar happened during the last "latest" migration. Unclear if we are running into the same issue again.

[detule]

I just checked, this is still needed ( not fixed in ubuntu 24 image ). I suggest we go with this in the short term. In the meantime I'll start researching possible solutions that will take us back to being able to use :latest.

[detule]

Closing in favor of #876