[Android] fix calculation to offset item in grid timetable

[tkhs0604]

Issue

• close #ISSUE_NUMBER

Overview (Required)

• Each item in grid layout starts from wrong position, so fixed it.
• The broken layout in day2 is the existing behavior, so keeping it as it is.

Links

Screenshot (Optional if screenshot test is present or unrelated to UI)

Day1	Day2

[github-actions[bot]]

Test Results

209 tests   209 :heavy_check_mark:  8m 0s :stopwatch:   11 suites      0 :zzz:   11 files        0 :x:

Results for commit ec5d3de5.

:recycle: This comment has been updated with latest results.

[github-actions[bot]]

Snapshot diff report	File name	Image
io.github.droidkaigi .confsched2023.sessi ons.section_null_Lan guage_TimetablePrevi ew-English-16_19_nul l_compare.png
io.github.droidkaigi .confsched2023.sessi ons.section_null_Lan guage_TimetablePrevi ew-Japanese-16_18_nu ll_compare.png
io.github.droidkaigi .confsched2023.sessi ons.section_null_The me_TimetablePreview- LightMode-26_26_null _compare.png
io.github.droidkaigi .confsched2023.sessi ons.section_null_The me_TimetablePreview- DarkMode-26_27null compare.png
TimetableScreenTest. checkScrollShot_comp are.png
TimetableScreenTest. checkGridShot_compar e.png
TimetableScreenTest. checkGridScrollShot_ compare.png

[takahirom]

@tkhs0604 I wanted not to use a fixed time for the start time. So I've changed a little. Could you take a look at it?

[github-actions[bot]]

Hi @takahirom! Codes seem to be unformatted. To resolve this issue, please run ./gradlew detekt --auto-correct and fix the results of ./gradlew lintDebug.. Thank you for your contribution.

[tkhs0604]

@takahirom I checked your commit and LGTM, thank you for improving 🙌