Optimize intellij plugin installation tests

[jan-vcapgemini]

What I still dislike is this stuff in the JUnit:

    String content = "plugin_id=mockedPlugin\nplugin_active=true\nplugin_url=http://customRepo";
    Files.write(this.context.getSettingsPath().resolve("intellij").resolve("plugins").resolve("MockedPlugin.properties"),
        content.getBytes(StandardCharsets.UTF_8));

We have solved this problem in other tests by adding plugin configuration properties file to the test project using a variable for the wiremock base URL and have some generic solution to replace the variable.
We should align IntellijTest with other tests using the better pattern, but let us not block this PR. Ready for merge.

Originally posted by @hohwille in #909 (review)

Hint:

We need to replace this workaround with 2 simple plugin property files (one with status active true and the other with active false)
See:

IDEasy/cli/src/test/java/com/devonfw/tools/ide/tool/intellij/IntellijTest.java

Lines 189 to 201 in 58fd72a

	private void setupMockedPlugin(boolean mockedPluginActive) throws IOException {
	String content = "plugin_id=mockedPlugin\nplugin_active=" + mockedPluginActive;
	Files.write(this.context.getSettingsPath().resolve("intellij").resolve("plugins").resolve("MockedPlugin.properties"),
	content.getBytes(StandardCharsets.UTF_8));
	}
	private void setupMockedPluginWithCustomToolUrl() throws IOException {
	String content = "plugin_id=mockedPlugin\nplugin_active=true\nplugin_url=http://customRepo";
	Files.write(this.context.getSettingsPath().resolve("intellij").resolve("plugins").resolve("MockedPlugin.properties"),
	content.getBytes(StandardCharsets.UTF_8));
	}