Description:
Pycharm package uses /usr/bin/pycharm to start /usr/share/pycharm/bin/pycharm.sh
This launcher checks absence $PYCHARM_JDK variable to see if it needs to fallback to system JDK.
However, pycharm.sh has its own mechanism to find JDK to use. One of the IDE features
is to force jetbrains recommended jdk which can be installed from "Choose Boot Runtime for the IDE".
This mechanism updates jdk version inside ${XDG_CONFIG_HOME}/JetBrains/PyCharmCE2023.1/pycharm.jdk.
Unfortunately, forcing $PYCHARM_JDK will force pycharm to ignore configs.
pycharm.sh:
# ---------------------------------------------------------------------
# Locate a JRE installation directory command -v will be used to run the IDE.
# Try (in order): $PYCHARM_JDK, .../pycharm.jdk, .../jbr, $JDK_HOME, $JAVA_HOME, "java" in $PATH.
# ---------------------------------------------------------------------

This behaviour is causing confusion when investigating jdk specific failures. See this bug report for example:
https://intellij-support.jetbrains.com/hc/en-us/community/posts/360007647099-Creating-a-new-file-won-t-focus-the-filename-input
where system jdk version is causing ui glitches.

As a solution, we may want to check the presence of pycharm.jdk file as well as env variable to match upstream package behaviour.

Additional info:
* pycharm-community-edition 2023.1.3-1

Steps to reproduce:
- install and run pycharm
- check Help > About for the jdk version
- do "Choose Boot Runtime for the IDE" and select any of (bundled by default) versions.
- restart pycharm when requested by install
- check Help > About for the jdk version and observe that it still uses system jdk despite it downloading new one and writing its path to pycharm.jdk