Remove UT TODOs and clean up related tests

[skliper]

Checklist (Please check before submitting)

• I reviewed the Contributing Guide.
• I reviewed the README file to see if the feature is in the major future work.
• I performed a cursory search to see if the feature request is relevant, not redundant, nor in conflict with other tickets.

Is your feature request related to a problem? Please describe.

HK/unit-test/hk_app_tests.c

Lines 1192 to 1208 in fbb231e

	void Test_HK_SendCombinedHKCmd(void)
	{
	/* Arrange */
	CFE_SB_Buffer_t DummyBuf;
	uint8 call_count_HK_SendCombinedHkPacket;
	/* TODO set return value of CFE_SB_GetUserData and check input to
	HK_SendCombinedHkPacket */
	/* Act */
	HK_SendCombinedHKCmd(&DummyBuf);
	call_count_HK_SendCombinedHkPacket = UT_GetStubCount(UT_KEY(HK_SendCombinedHkPacket));
	/* Assert */
	UtAssert_INT32_EQ(call_count_HK_SendCombinedHkPacket, 1);
	}

Describe the solution you'd like
Remove TODO and clean

Describe alternatives you've considered
None

Additional context
None

Requester Info
Jacob Hageman - NASA/GSFC