[cmake] Remove redundant find_package(Python)

Summary: These calls are no-op because the FindPython for the interpreter is already called in the main CMakeLists.txt (and the variable is cached). Also these calls don't make it mandatory nor enforce a minimum version which is confusing.

Test Plan:
  ninja all check-all

Reviewers: #bitcoin_abc, PiRK

Reviewed By: #bitcoin_abc, PiRK

Differential Revision: https://reviews.bitcoinabc.org/D16947

cmake/modules/Coverage.cmake

@@ -55,8 +55,7 @@ function(enable_coverage ENABLE_BRANCH_COVERAGE)
 	find_program_or_fail(GCOV_EXECUTABLE gcov)
 	find_program_or_fail(GENHTML_EXECUTABLE genhtml)
 	find_program_or_fail(CXXFILT_EXECUTABLE c++filt)
-	find_package(Python3 COMPONENTS Interpreter REQUIRED)
-	set(__COVERAGE_PYTHON "${Python3_EXECUTABLE}" CACHE PATH "Path to the Python interpreter")
+	set(__COVERAGE_PYTHON "${Python_EXECUTABLE}" CACHE PATH "Path to the Python interpreter")
 
 	get_property(_project_languages GLOBAL PROPERTY ENABLED_LANGUAGES)
 	set(COVERAGE_FLAG --coverage)